HW77K in pieces

Tuning a Weihrauch HW77K air rifle at home – Part 1

How to DIY tune a HW77K spring airgun: Part 1

Tuning a HW77K Weihrauch air rifle or other spring powered air gun beats shooting a rifle in the factory “default” condition, which by most standards is pretty basic. There are a few prerequisites that need to be followed prior to diving in and stripping your Weihrauch air rifle with the view to tuning it.

  • Firstly, if you are a lousy shot, then save your time and money because a tuned air rifle will not make you a better shot and you won’t be able to blame the rifle…
  • If the air rifle is brand new then I suggest that you consider shooting around 1500 shots through it to bed it in. This will allow you to develop a shooting profile, consistent grouping (be it good or bad) and muscle memory. This is important because it will give you a datum to compare your tuning to the original performance of your air rifle.
  • You will need some basic mechanical aptitude and by that I mean you need to know one end of a hammer from the other…

Before you start on in, consider whether or not you feel you have the confidence and basic skill set to do a neat job. If not, then maybe you should recruit a mate who is more technically inclined, because tuning a HW77K needs a degree of competency. However, should you get stuck doing the tune-up, you can always call me, and I can talk you through it, even if you purchased your air rifle elsewhere…. hmmm.

Tuning a HW77K: tool requirements

Let’s look at what tools you will need here so that you do not get halfway and get stuck for lack of tooling.

  1. Metric Open end/ring spanner set up to 13mm.
  2. Ball Pein (aka Ball Peen) hammer 12 – 16oz (small to medium).
  3. Pin punches – Long Series 2.5mm, 3mm and 4mm will get you by.
  4. Metric Allen Key set to 6mm.
  5. Flat screwdrivers to suit the stock screws.
  6. A cradle of some kind to support the action and/or stock.
  7. Buffing machine (Bench grinder with Buffing attachment – see image below).
  8. Workbench (Kitchen Table/Dining Table would be nice when the wife is out shopping…) that is clean and covered with a cloth base to protect the rifle parts.
  9. Bench vice.
  10. Cleaning fluid – degreasing spray or mineral turps etc.
  11. Moly grease and a suitable oil.
  12. Several containers – 1 for parts to be cleaned, another for clean parts and a 3rd for tools etc.

Your workbench should be clean and covered with an old sheet or similar material to minimise stock scratching and making unsightly marks to the bluing. Do not use a blanket as it will leave fine strands on material sticking to oiled parts of your air rifle. You need a container for parts and good lighting as the bluing is easy to scratch and difficult to repair. Keep all your tools well clear of your air rifle as it is too easily mark your bluing or stock on some sharp edge of a wayward tool lying close by.

The buffing machine can be your typical bench grinder with the accessory spindle fitted to take buffing wheels. The images below show 2 buffs, the dark one is used for initial prep work using a fine compound like Autosol metal polish and the light coloured buff is an ultra fine cloth to finish the steel to a fine polish without anymore compound. I do NOT advocate using the bars of a compound often used with buffs as these can be a bit savage. Should you end up taking off too much metal (rather than just polishing it) it will prove to be an expensive exercise.

Fine Buffing wheel   Ultra fine buffing wheel

                                         Fine Polishing Buff                                                                                Very Fine  Polishing Buff

Polish for air rifle tuning

Autosol Polish For Fine Work.

Stripping the Air Rifle

Start by making sure the air rifle is not loaded or cocked – this may sound kind of elementary but “empty” guns have killed more people than smallpox… not literally, but you can see where I am going with this. Just check the damn thing.

With the Weihrauch HW77K, turn the rifle upside down in a cradle that will support it leaving your hands free. Then start by loosening (half a turn will do) the small screw behind the trigger guard, then the main spigot screw in front of the guard and lastly the 2 opposing fore-end screws. With all 4 screws loose you can then remove them from the rifle and place them together with the fore-end washers into a container. Separate the action from the stock and place the stock away from your work area leaving the action clear of all tools and crap you may have on the bench.

Weihrauch HW77K Air Rifle stripped down

Weihrauch HW77K Air Rifle action out of the stock.

Using a 13mm metric open-end spanner, undo the spigot pin and spacer (numbered “1” in the image below) and place these in a container.

We can then continue the strip down the air rifle by first releasing the loading arm from the fore end detent by pushing in the button beneath the front of the barrel. Then select a 3mm pin punch or one close to the pin diameter which is just forward of the bridge mount which is attached by the 2 fore-end stock screws. In the image below it is numbered “2”. Cradle the action over a couple of wood blocks covered with towelling and tap through the pin. You can then lift the loading arm and disengage it from the action, placing it well away from the rest of the air rifle action.

When looking at the action of the HW77k Weihrauch Air Rifle cast an eye over the pins and you will see on one side the 2 pins that hold the trigger group have a recessed flat on one side of the action where each pin is located. This is the side you insert the pins when putting them back and this is the side they get pushed out of (pushed out from the other side).

The blued pressed metal slide is known as the anti-beartrap (“3”) which is designed to slide between the trigger pivot and action the moment the loading arm is released. The idea is to stop some clown from pressing the trigger when the loading arm is down in the loading position: this could result in some painful fingers if they are putting a pellet into the barrel at the same time. Don’t worry, it’s been done I know.

Next tap out the 2 pins (“4”) holding in the trigger group and put them aside in a container. This will allow you to remove the trigger group from the action. While the image below does not show it, the safety catch should be removed at this point together with its compression spring.

You should now have your rifle stripped to the following as shown in the image below.

Weihrauch HW77K (Nickel) initial strip-down.

Weihrauch HW77K Air Rifle (Nickel) initial strip-down.

Once you get to this point, clean everything away on your bench as you will need to pull apart the action next. Cleanliness in tuning a HW77K does not stop at keeping the rifle clean. If you want accuracy and longevity in your HW77K or any air gun for that matter, keep your pellets clean too. The best way to do that is with a Pellet Pouch and not your grubby pockets.

I can’t stress this enough, and that is to work in a clean and well-lit environment with tools and other miscellaneous bits and pieces well away from your air rifle as marking it is just too easily done. For those of you who are familiar with pulling down air rifles, these points may seem a bit lame or even basic. However, I can assure you from the phone calls that I get, there are a large number of air gun owners who know nothing about stripping down an air rifle.

The next thing we need to do with the HW77K is unwind the trigger housing from the main body of the action. You should find this very tight and may well need to put a close fitting spanner end into the trigger group recess. When doing this, find a large spanner with a thickness very close to that of the trigger group, place it deep into the slot, then while holding onto the main body, strike the spanner so that it twists the trigger housing in an anti-clockwise motion. Once the trigger housing starts to move, I suggest that you undo it by hand while watching how much thread is still left in the housing. Once you get down to about 4 or 5 threads left (looking through the loading arm channel under the main body), it is time to place the air rifle down and fasten a clamp across it from the barrel end to the trigger housing end.

Do NOT unwind the air rifle trigger housing all the way by hand as it may fly out the end with a terrific force and if it hits you, it won’t do you any good at all.

On 12 Fpe air rifles the spring compression is such that you can, with some common sense, undo the trigger housing while pressing down while unwinding – this is done with the air rifle facing upwards at 90 degrees and you holding down the trigger housing while you unwind it. However, in the interest of getting you to safely unwind the two housings, I would prefer you to do it this next way as it is safer.

The safe way to disassemble a springer

I use an Irwin sliding clamp as pictured and lightly oil each pad then tighten it gently holding the barrel end and trigger housing in the centre of the clamping pads. This is easily accomplished when laying the components down flat. Once you have taken up the slack in the sliding clamp and have applied a bit of pressure on the air rifle you can unwind the rest of the action without it flying apart.

I also put the rifle together using the reverse of this clamping method. See the Irwin clamp that I use, it has a 920mm opening and works very well. I purchased it from Bunnings for around $36 I think.

Irwin Clamp used when tuning a HW77K

Irwin Sliding Clamp With 920mm Opening.

Tuning a HW77K part 1, the air rifle components.

Once you have separated the housings you should have the following on your bench that will require cleaning, inspecting and then polishing before being re-assembled.

Weihrauch HW77K components

HW77K Air Rifle in pieces.

Now you have got this far, the next thing we will move onto is Part 2 of this tuning article following: that will cover inspecting, actual polishing and assembly options pertaining to the Weihrauch HW77K air rifle. A lot of what I have here also applied to other airguns even though I am targeting tuning a HW77K Weihrauch.

Author: Ian McIntosh, Gunroom

HW77K in pieces

Tuning a Weihrauch HW77K air rifle at home – Part 2

How to DIY tune a HW77K spring airgun: Part 2

If you have followed Part 1 of Tuning a Weihrauch HW77K air rifle at home, you should by now have your Weihrauch HW77K or another air rifle completely stripped down with the exception of the trigger group that remains assembled.

At this point, we need to de-grease the entire collection of air rifle parts, inspect them for wear and damage and replace anything as a result. You will need to carefully prise the piston seal off if you are going to keep it, however, if you are going to replace it then you can cut it off.

Caution: The Weihrauch HW77K /HW77/HW97K have 2 piston sizes, one is 25mm up to serial #1446048 with the 26mm piston seal fitting all rifles with the serial #1446049 and above.

Identifying the Air Rifle Components for Polishing

The HW77K Air Rifle trigger group sits in what’s commonly called the Back Block which forms part of the barrel and action and is not sold separately. You will see that the end facing forward that faces the spring end is rather crudely machined, see below:

HW77k Air Rifle Block Unpolished

HW77K Air Rifle Back Block

This face is the first part that I polish, by using a Fine Buff and the Autosol Metal Polish. Be careful to keep the Buff on the face and do not let it stray onto the thread leading off from the face as this will wear rapidly under the Buff friction and polish. Basically, we are improving the Weihrauch HW77K’s parts by reducing friction and make it air rifle load and fire more smoothly. It works, period.

If your back block face has heavy machine marks, then I would advocate doing the initial work on some oiled Wet & Dry 400 Grit Carborundum paper on a sheet of glass to keep the face edge flat. Once you have taken off the machine marks for the most part, then continue with the Buff.

Finish the Buffing with the Ultra Fine Buff with NO metal polish, just aim for a high lustre.

The idea is to polish the face and not grind the crap out of it. You will likely still get cutter marks (aka Tram Lines) on the face as seen on the image below but as long as the face is polished these marks are of no concern. See below:

HW77K Back Block Polished

Air Rifle Back Block Polished

While you can’t see down the bore of this back block, I did run a light Carborundum paper in a slotted brass post down it and took out the worst of the drilling marks.

Next, I focus on the air rifle cylinder and start by de-burring the loading arm trap at the end of the cylinder. Failure to de-burr can result in a small nick to the piston seal when you are assembling the unit. I use a Dremel with a small stone (2mm) and come in from above onto the rectangular slot as seen in the image below.

If you mark the bore at the end of the cylinder where the loading arm slot is, that should not pose any problems as the piston seal does NOT come back that far that it would ride over any grind marks in this area. All the same, care should be taken.

If you shake like a Granny at a Christening then it would pay for you to put some masking tape from the opening in as far as the loading arm slot. This way as you shake your way through de-burring, you are less likely to penetrate the tape and damage the cylinder bore.

You can see the de-burred loading arm slot in this image below:

Cylinder HW77K Air Rifle

HW77K Cylinder

From here I move to polish the air rifle cylinder outer using a Fine Buff and Autosol Polish. I rotate the cylinder slowly while keeping the Fine Buff working a small area of metal polish. The idea is to either run up and down polishing it and slowly rotating as you go, or polish around the cylinder and work your way from one end to the other. Your choice.

Once you can see the machine marks are on their way out, swap over to the Ultra Fine Buff with no polish and buff to a lustre. Keep an eye on how much metal you are removing, because in fact that is what is happening, be it slowly. I would suggest that you do the buffing very slowly and take care not to mark the cylinder with some careless buffing or by dropping a hot cylinder. That is correct, you can expect the cylinder to get pretty hot so I also suggest gloves and glasses to protect yourself further.

Your cylinder should end up looking like this on the left of the piston:

Weihrauch Piston and Cylinder

HW77K Air Rifle Cylinder and Piston.

Note: Do NOT polish the inside of the cylinder as it has hone marks in it to trap lubricant so just leave it be after cleaning.

I then polish the piston (without the seal fitted…) and the release catch the same way as we have polished the cylinder. Below I have 3 images showing the Cylinder, Piston and Back Block polished:

HW77K Piston and cylinder ends

HW77K Piston and Sleeve Polished

Piston End HW77K Air Rifle

Polished Components.

HW77K Back Block and Catch

Polished Block & Piston Assy

When polishing the catch on the end of the piston, do NOT overdo this and end up changing the lug’s leading edge profile, you only have to polish it using metal polish and buff it with the Ultra Fine Buff with no polish.

Once you have got this far, you might be wise you lightly oil these components as humidity or damp fingers can leave unsightly marks and even slight rust stains.

Next, we need to focus on the spring and you need to consider swapping it out if the spring has a lateral bend in it, is worn (inconsistent gaps between coils) or has done a lot of work. Of course, if you are fitting a Vortek kit then you would be replacing the spring, but it still needs work as follows:

The spring on the left has been removed from a new HW77K and has been de-greased.

You will notice the grind marks on the spring end and the sharp edges of the spring.

Firstly I would polish the spring ends on a Carborundum paper on a sheet of thick glass with oil to take out the worst grind marks. See following image below.

Weihrauch Air Rifle Spring

Old Spring

Polishing Air Rifle Spring by hand

Polishing an Air Rifle Spring

Once you have done this then the sharp edges need de-burring with a Dremel or similar: don’t get carried away, just take off the sharp edges.

Then it is time to buff the spring but take care that the buff does not catch in the spring ends as it can tear out of your hands easily.

Once the grind marks have been polished on the Carborundum paper and the edges de-burred, polish the spring ends to a lustre as below:

Polished HW77K Spring End

Polished Air Rifle Spring

Repeat this with both ends of the spring and use your fingers to check for sharp edges by rubbing them into the ends of the spring. Any sharp edge, stone it and polish it out.

Air Rifle Spring Polished

Next comes the Spring Cushion Guide which has a finish as below left before polishing on the right:

Weihrauch Spring Cushion Guide

Spring Cushion Standard

Polished HW77K Spring Cushion

Spring Cushion Polished

You will note that even after polishing the spring cushion still has machine marks that are OK as long as they are polished.

HW77K Internal Components

Polished Assembly

So if you have come this far, you should have a collection of parts as in the above image, cleaned, highly polished and lightly lubricated until you are ready to reassemble the air rifle.

Tuning the HW77K: Summary of Polishing the Air Rifle Components

While this article is based on the tuning the HW77K, the components for the HW77 and the HW97K are exactly the same. However, if you have another model of Weihrauch Air Rifle or a different make of spring powered air rifle, the process is still the same. You may or may not have a separate cylinder like the HW77K as the piston may run inside the air rifle outer action, or you may have a side loading action, break barrel or whatever, it is still the same process.

You need to focus on cleanliness when stripping an air rifle and then going to these extremes to polish up the components. Your working environment needs to be clean and have a soft cotton cloth (preferably) base to put the parts on to minimise scratching or marking.

The next article is Part 3 and I will cover assembling the air rifle, lubricating it and testing it through a Chronograph. The last article on tuning the Weihrauch HW77K, Part 4, will cover pellet selection and tuning using pellet types in your air rifle.

Author: Ian McIntosh, Gunroom

HW77K in pieces

Tuning a Weihrauch HW77K air rifle at home – Part 3

How to DIY tune a HW77K spring airgun: Part 3

Hi guys, tuning Weihrauchs refers to the HW77, HW77K and HW97K that are the subject of this article, Most of what I discuss here applies to other air rifles too, though I will make continual reference to the HW77K. Apologies for the delay in getting part 3 out but running this site and business on my own just eats up the hours leaving little time for articles. I have simplified this assembly procedure as much as I can to assist those of you who are perhaps tuning their first air rifle even if it is not a Weihrauch HW77K.

Check out part one and part two of this airgun tuning article series if you haven’t seen it already.

I am going to assume that you now have the Weihrauch air rifle in bits, polished and ready for assembly. That said, all the rifle parts you have should be lubed with a thin coat of oil if they are being left to stand for a day or two. Now the assembly and testing I am going to outline here is the way I do it, that is to say, it works for me but this is not the ONLY way to go.

Even though the parts are lubed after polishing to stop corrosion etc., I like to wipe them clean and dry and finally inspect them and re-lube them as I assemble each piece. This ensures that no dirt or foreign matter is stuck to any parts that have been zealously lubricated.

Tuning Weihrauch springers: Assembling your piston seal

Before you start reassembly, clean your bench of tools, parts, beer cans and crap so that there is no chance you can scratch or mark your parts or the bluing of your rifle. With the Weihrauch HW77K, I start assembly by fitting the piston seal. I put the seal face down (recess up) on a clean cloth, (key word here is ‘clean’…) and using a cotton bud I put a small amount of Moly grease on the inside of the seal retaining wall and the rebated edge of the seal. Don’t over-do this guys, as too much grease will only result in it being displaced onto the cylinder wall and then finding its way to the front of the seal, where ‘dieseling’ can occur.

Once I have a thin coating of Moly on the internal edges of the seal, I lightly coat the piston flange outer (front of the piston). Then by placing the piston face down on top of the seal, you can ‘walk’ the piston into the seal recess by pressing down hard and moving the piston side to side slightly from the vertical while rotating it by hand, and so allowing the edge of the piston face to slide into the seal recess.

NOTE: Do NOT use a hammer, screwdriver or the like, as there is a high probability that you will not only bruise the seal and create a weakened area, but you may puncture the seal or mark the leading edge.

Once you have the seal mounted onto the piston, rotate the piston while holding the seal with your fingers to ensure that the seal is correctly fitted, it can rotate freely and that the contact areas have sufficient lube. If you can’t rotate the seal by hand then you need to remove it and check that you have in fact got the correct seal and/or sufficient lube.

Note: On the Weihrauch HW77/97 group, air rifles earlier than 1446048 have a 25mm seal while the later units have a 26mm seal. Don’t get his wrong as it will cost you in time and occasionally damage to the sleeve. The seals are very close in size and that has lead to mistakes being made by some in the past.

Weihrauch seals are pretty soft and flexible and dead easy to mount, however, Vortek Vac-Seals and PTFE seals are another matter. Light lube on the contact areas and vertical positioning of the piston while rotating it is the key. Do not use a press or clamp. If you get stuck and you are living in Australia, give me a call, any time and any day and I think we can sort out any problem on the phone (I will call you back).

OK, so let us assume that you have jumped this hurdle and the seal is fitted and rotates freely. I then fit the spring guide that comes with the tuning kit, ensuring that the open edge is 180 degrees away from the slot in the piston (V-Mach kit). If you are reassembling your air gun without the kit, then skip this last bit as Weihrauch air rifles do not come out with spring guides. If you are fitting a Vortek kit, skip this part as well.

Next, I wipe down the piston and seal outer to ensure that there are no grease or cloth particles sticking to it. I then LIGHTLY (keyword again…) grease the piston and the seal sides ensuring that there is no grease on the face of the seal. Then stand the piston upon the face of the seal somewhere where you won’t knock it over if you are assembling on a clean material.

HW77k Exploded Image for Tuning Weihrauchs article

HW77K ready to assemble (Note Trigger group is in the “fired” position.)

Tuning Weihrauch springers: Compression Tube & Piston Assembly

Next, you need to pick up the compression tube and wipe it clean of any debris, lube and fingerprints etc. It needs to be clean and dry as your hands. Face the chamber downwards and lightly smear a bit of Moly grease into the first 30-40mm of the inside of the chamber wall. Then pick up the piston and carefully marry it up to the cylinder. You may have to ‘walk’ this around by rotating the piston/seal slightly in the open face of the compression tube while rotating it, similar to what you did fitting the piston seal.

Once you have the piston seal entering the sleeve you can push the piston home until it bottoms out, then pull the piston right out of the cylinder and wipe off any grease that has migrated to the face of the seal. Repeat this a number of times until negligible grease is evident on the seal face. By working the piston in and out you should be able to determine if there is any binding or change in the wall diameter as this would be evident in the pressure required to move the piston.

If you use a standard Weihrauch Seal when tuning the air gun, you will notice that the wall tension is much less than that of a PTFE seal, with a Vac Seal rating somewhere between both of these seals in wall tension. Cost-wise the Weihrauch seal is the cheapest followed by the PTFE seal then the Vac Seal with each seal have different unique qualities apart from price.

When you are happy with the piston and cylinder set being assembled and lubricated correctly you need to move onto the chamber. If you have an air rifle that does not use the compression tube like the Weihrauch HW77s and HW97K models do, then treat the rifle chamber as I have detailed above for the compression tube.

I then wash out the chamber with degreasing spray (Cheap Auto-Parts sell cans for around $2.50) and a swab on a wood dowel, usually at a point in time when my wife is out of the house. That enables me to rinse out the chamber and barrel assembly using hot water and detergent in the sink. When clean I wipe it down carefully (the sink that is… and then the Weihrauch action) with clean towelling or one of my tee shirts.  I then blow out the barrel and action points with compressed air. Don’t get caught doing this as women just don’t understand…

Satisfied that the action and barrel are clean and dry, I lubricate the inner chamber wall and then fit the compression tube and piston. With compression tubes that are polished to a high degree along with inner chambers being polished too, you will find that loading the air rifle will be very smooth indeed. When lubricating these 2 parts, there is no real danger of over lubricating them as any excess grease will soon be evident in the loading gate or at the rear where the compression tube is housed. It can be removed then.

The spring is then wiped clean of lube, inspected and re-lubed prior to final fitting. If you are fitting a tuning kit, now is the time to fit the recommended number of washers beneath the spring.

Slide in the compression tube complete assembly and check that the long slot in the tube is facing out (down while holding the rifle horizontally) and that will be evident when the compression tube marries up with the offset barrel port that extends into the loading port by around 3mm. If your air rifle is new then leave the barrel seal in that came with the rifle but if it has done a few miles, change it for an ‘after-market’ seal. These are made in the USA and seal very well with quite a soft material.

HW77K Piston Sleeve. From Tuning Weihrauchs article.

Piston Sleeve and Spring Assembly in the correct position. If you use a V-Mach spring guide then fit it with the join facing upwards, that is towards the top of the air rifle. The above image has a V-Mach kit in it and the lower portion of the spring guide can be seen through the loading arm slot.

Once you have the compression tube pushed home and fully engaged (above) with the barrel port, I fit the loading arm catch into the compression tube and lock it onto the piston. I then tie it up against the air rifle’s action with a cable tie. This is done to stop the piston rotating in the chamber when the breech block is screwed back on. See Below:

Loading Arm – Piston Sleeve from Tuning Weihrauchs article.

The Loading Arm Lever is hooked into the Piston Sleeve

Loading arm in position HW77K from Tuning Weihrauchs article.

This image shows the loading arm is inserted into the Piston Sleeve.

I hold the loading arm with a Cable Tie on sub 12 Ft Lbs springs but on FAC springs I hold the loading arm by partially inserting the pivot pin and setting the outer arm into the detent as you would do prior to firing the air rifle. See below:

Weihrauch Pivot Pin HW77K from Tuning Weihrauchs article.

The partially fitted pivot pin

At this point screw the breach block on using a sliding clamp as illustrated in part 1 of this article. Before you put it in place, lightly grease the face of the breech block and the loading arm catch that enters it. I also put grease on the rear of the breech block so that I can turn the block when it is under pressure of the sliding clamp. I put a small amount of oil on the breach block threads at this point.

Compressing Loading Spring HW77K

Irwin Clamp – Piston, barrel and spring assembly being compressed into the breech assembly.

I then tighten up the clamp slowly until I see the thread of the breach block mate up with the thread in the action housing. At this point look along the air rifle assembly to ascertain that the breach block and chamber are inline. Then carefully turn the breach block until the action thread is engaged.

Note: Keep an eye on the alignment here as on powerful springers the 2 assemblies can ‘walk out’ of the clamp alignment and possibly exit at great speed. The key here is to do this slowly if you are a first timer.

Then screw the breech block home and tighten until the trigger opening is aligned correctly. You can also use the dovetail on top to ensure that the mated parts are aligned by running your fingernail along the dovetail to check for alignment.

Alignment is done by placing a brass drift that fits snuggly into the trigger recess and tapping it around once it tightens up by hand. I say “tapping” because it only takes a small amount of pressure to tighten and align the two components. If you over-tighten the breach block then you may find that it becomes loose down the track. To overcome that problem you will need to Loctite the two parts with medium grade Loctite or equivalent, but only do this if your components have been over-tightened quite severely or are prone to loosen on older air rifles.

Weihrauch HW77K end cap.

Threaded end cap partially installed while still in the clamp. At this point, you can disengage the clamp and tighten by hand.

Weihrauch Trigger pod from article Tuning Weihrachs

Tightened End Cap Assembly ready for Trigger Group.

Weihrauch Rekord trigger from Tuning Weihrauchs

Trigger Group in the ‘Open’ or ‘Fired’ position

Press down the Top Lever and catch it with the trigger sear floating arm and it will then be in the ‘Loaded’ position and look like the image below here:

Weihrauch Rekord trigger 2 from Tuning Weihrauchs

Trigger Group in the ‘Loaded’ position and ready to install.


Once you have the breech block tightened up and aligned you will need to fit the trigger assembly. Firstly you need to ensure that the trigger group is sufficiently lubricated and then you need to “load” the trigger as per the images above. Once the latch is engaged you can drop the trigger group into the recess and work it down keeping it parallel with the housing. The safety catch is then lubricated and inserted with the spring fitted on the catch end. Hold the safety in against the spring pressure and gently manoeuvre the trigger group into position on top of it.

At this point, I feed 2 tapered pins through the locating holes so that they engage the trigger group and align it ready for the long and short retaining pins. I put them in from the side as shown below and just far enough to locate the trigger group and hold it in place. Then you should be able to slightly rock the trigger group while still holding the safety catch to ensure no binding of the safety catch or trigger assembly occurs. I now slide in one pin at the opposite side and lightly tap it through so that the tapered pin is dislodged, and the retaining pin replaces it through the trigger group locating the hole. The safety catch should still have a small amount of movement in it without binding.

Assembling Weihrauch Trigger from Tuning Weihrauchs

Locating the Trigger Group and Safety Catch to ensure that there is no binding prior to installing location pins. Apologies for the crappy image.

Then repeat this with the second retaining pin while still gently rocking the trigger group and safety catch until the tapered pin is replaced. I then drift the pins into place using a small ball pein hammer and pin punch until the pins are equidistant through the housing. You can then press the trigger and the loading catch will be released with an audible ‘click’.

The loading arm can now be cut free of the cable tie and removed, cleaned and assembled with the ‘bear trap’. The loading arm pivot pins are quite often a loose fit and if your air rifle’s pin falls into this category, do the following:

The bear trap and loading arm are refitted so that the loading latch is located correctly and the pivot aligned with the hole. Prior to alignment, lightly oil the pivot pin arms and locating hole.  With the pivot pin clean and dry, insert it through one side of the chamber boss and into the 2 pivot flanges until about 3mm is still protruding from the boss. Put a drop of Loctite on this dry pin and then press it home. Note that the final 3mm of travel must be free of oil or lube so that the Loctite can securely hold the pin against any movement.

Before you engage the loading arm into the end of the barrel detent, make sure that the bear trap is located at the end of the latch, otherwise, there is a better than even chance the loading arm catch may bend the bear trap. At this point, I push the bear trap platform towards the trigger so that the anchor stud can be threaded into the action. While tightening the anchor stud you need to rock the loading arm up and down to ensure that the stud does not crimp the bear trap. The anchor stud has a small spacer under it to give clearance to the bear trap. Once you have tightened the anchor stud, make sure that the bear trap platform moves under the trigger pawl the moment the loading arm is released from the barrel detent. Lightly oil the bear trap once you are satisfied that it is functional.

Note: Never remove and discard the bear trap as the rifle may then be fired (inadvertently) while your fingers are putting a pellet into the barrel. It WILL hurt if it lets go…

Tuning Weihrauch springers: The final assembly

So now we should have the HW77K air rifle assembled and ready to mate with the stock. Wipe down the action with a clean rag will a small amount of oil on it. Make sure that the small nut is still in place at the rear of the trigger group as this has a habit of dropping out of the trigger housing when inverted. Then I suggest that you wipe down the internals of your gun stock to ensure that there is no debris, oil or grease that can migrate onto your clean action.

Assemble the two components together and fit all 4 screws (we are talking about the Weihrauch HW77 and HW97k here) but do NOT tighten them at this stage. Now I hold the rifle vertically with the butt pad on the bench and while pressing down on the barrel, effectively pushing the action rearwards into the stock, I tighten the anchor stud first. Follow this with tightening the two forward stock screws and lastly the small rear trigger group screw. Always undo the screws in the reverse order.

Doing it this way ensures that the rifle action is hard back against the timber/synthetic stock and ultimately puts less strain on the anchor stud through recoil. Do not tighten up the rear screw ahead of the anchor stud as this screw is small and does not bottom out when tightened. The anchor stud is capable of bending the trigger group when tightened if the small crew is, in fact, pulled down first.

If you have experienced your rifle coming lose in the stock due to recoil, what I do is the following:

With all the screws loosened I stand the Weihrauch airgun vertically and measure the distance between the rear of the breech block and the stock with feeler gauges or similar. I then cut a half moon shape out of black plastic (you can use whatever it takes) from a piece of scrap laying around and fit it between the breech block and the stock rear (make it slightly thicker than the opening when under pressure). If you push down on the barrel while being held vertically, you should not be able to pull the plastic spacer free. Then tighten the screws in the order above while downward vertical pressure is applied.

By fitting this small half-moon spacer we are effectively transferring the recoil through the spacer into the stock rather than through the anchor stud that is prone to coming lose with some of the heavy recoiling Weihrauch air rifles.

The Weihrauch air rifle can now be test fired once you are satisfied that the loading arm effectively activates the bear trap and that the safety works correctly. After tuning you should notice a definite reduction in recoil and spring noise that will help with accuracy while putting less pressure on the mechanicals of your scope. Part #4 will cover pellet selection and tuning the Weihrauch HW77 air rifle. Remember, if you have a problem with a Weihrauch Australia wide, not just when tuning Weihrauchs, then please contact me, any time, any day and I will endeavour to assist you.

Author: Ian McIntosh, Gunroom

HW77K in pieces

Tuning a Weihrauch HW77K air rifle at home – Part 4

How to DIY tune a HW77K spring airgun: Part 4

Tuning Weihrauch air rifles is one task that most guys skip over and if they endeavour to “tune” their springer, they seldom follow a recognised series of steps that need to be followed to the letter ( if you want the best from your gun that is). It is not a “five-minute” process and in fact, can result in pulling down a gun many times to get it right. One HW77K that comes to mind, took me 14 rebuilds and adjustments to reduce the group from 48mm at 30 metres down to 8mm at 30 metres. In fact, throughout the competitive life of a spring air rifle, it needs constant adjustment and resetting to get the optimum performance from it.

What I am putting forward here is how I do it and there are others who are tuning Weihrauch air rifles that do it differently than myself, with each of us getting there in the end with the results we want (most of the time that is…). Tuning Weihrauch air rifles does not stop at fitting a Vortek or V-Mach kit. That is but one of the first steps and I will assume that you now have a kit in your Weihrauch HW77, HW77K or HW97K and wish to complete the tuning cycle. Tuning a HW97K will be exactly the same procedure.

Air rifles Australia wide are usually FAC classed and this tends to reduce their accuracy to a degree when put against a 12Fpe air rifles that they use in the UK.

Check out part one and part two and part three of this airgun tuning article series if you haven’t them already.

Test Fire your air rifle

If you have fitted the kit and assembled the rifle then you will need to check that it functions correctly. So take extra care loading the gun and placing your digits in the loading port, should the trigger let go, it will hurt I reckon. You need to test the bear trap works while holding the loading arm down (do NOT let go of it…) and then you need to test the safety while pointing the air rifle at a backstop capable of trapping a pellet.

Fast forward here. Let us assume that the assembly went well, the bear trap works, you haven’t lost any fingers and the safety works well. Now set up a target at no more than 20 metres as we are but testing the rifle, not competing yet.

At this point, I usually put through 20 or so shots using H&N Baracudas and pepper the target. The reason I put through 20 shots is that the grouping tends to change after a few shots as the rifle seal beds in and the spring develops a ‘set’ etc. 20 shots will give you a good idea of how it groups and feels and will allow you to re-zero the scope.

Then with a new target, I put 10 shots into it recording the speeds, energies, extreme spread and standard deviation. This gives you a benchmark to start tuning. If you do not have a chronograph and you can’t borrow one, then rely on your grouping and follow along.

Tuning Weihrauch air rifles: Pellet Selection Testing

Know this, the perfect pellet does not exist that suits every air rifle, period. You would have a better chance of finding Keyser Söze than the perfect pellet, so don’t bother looking.

At this point I get out a good cross-section of pellets, sometimes as many as 15 or more types, to put through the air rifle to find a suitable match for the gun. You need to understand that every air rifle is different and each gun has its own “DNA” for want of a term, so now you need to find which pellet type performs the best.

Next put in 10 shots per target without changing your point of aim (POA) so that you can compare the trajectory of each pellet in your gun. Shooting only 3 pellets into a target does not give you the grouping, but 10 pellets do give you a good idea of where it’s at.

I generally narrow it down to between 6 and 10 pellet types, finally selecting the one with the tightest group. Which pellet this is, only testing will decide.

Tip #1. When aiming at the target I zero in on the circle in the centre of the 5 in a 6-circle target or the centre of the 9 in a 10-circle target – see image below. Aim small and miss small, aim large and miss greatly. I set the scope so that the pellets hit the bull (hopefully) below my POA. If you aim at the bull, it is fairly large, and you need to judge the centre which is harder to do that placing the reticle on a small circle. Then if you do hit the bull, the resultant damage to the bull with multiple shots makes judging the centre more difficult. You can always move the Point of Impact around the target with your scope settings.


Air Rifle Target Green

Air rifle targets in Green and Red.

Air Rifle Target Black

Black and white air rifle targets.

When you have found a pellet that is grouping well, then you can move onto getting it to group even better.

Your selected pellet type

At this point, I will use the H&N Baracuda Hunter as the “best” pellet in this exercise. This pellet supposedly weighs in at 18.21 grains for a .22 calibre pellet. However, if you weigh a bunch of these pellets using a digital jewellery scale that can measure down to .01  grains, you will find that these pellets can weigh anything from 18.10 to 18.30 and in-between.

To start the selection process so you can drill down and find the best weight for this pellet, you need to first inspect each pellet, yup, each individual pellet. Skip this process and you may as well fast forward to the end of this article.

Empty a few of tins of H&N Baracuda Hunter (in this example only) onto a soft towelling material and carefully pick up each pellet and inspect it for dents around the nose and more importantly, around the skirt. The pellet skirts are thinner and more prone to being deformed through rough handling and transport.

Place in one pile all the ‘good’ pellets and put the failed ones away from this process. Once I have around 200+ ‘good’ pellets I then wash them, 50 at a time, in a plastic jar with a sponge base so that the pellets do not get crushed. I use acetone and a 1” paint brush and gently brush the pellets around the bottom for half a minute or so. I then empty them into a plastic sieve and wash them under hot water, finally drying them in soft towelling.

Tip#2. Check that the sponge, plastic jar and paint brush can withstand Acetone by using a small amount as a trial.

Tip#3. Some guys use washing detergent instead of Acetone that works well too. Safer by a long shot but it needs closer inspection to see that no remaining manufacturing compound still remains on the pellets.

The idea of washing the pellets is to remove any factory added preservatives, anti-oxidants or lubrication necessary for the manufacturing process. I have seen some pellets with visible amounts of a “wax-like” compound in and around the skirts.

Once you have washed and dried your pellets you then need to weigh them on your digital weighing scale. I usually end up with up to 5 piles of pellets of different weights, that is +/- .02 grains.

Further Pellet Selection

In the next step, you need to arm yourself with pen and notebook and set up ready to test each individual pellet pile. Start with either the heaviest or lightest and fire 10 shots noting the speeds and groups obtained. Then work your way through the individual piles of pre-weighed pellets and you should find that a particular weight works best, giving you the best group.

Now do NOT expect to get marksmanship results doing this as it is only one brick in the tuning wall and there are more bricks to lay, so to speak.

I then record the best, next best and third group by pellet weight. Following this, I lube some of these pellets with Dry Lube sprayed onto a fine sponge and I lightly rub them around to cover them. Do not drown the pellets with dry lube but let the sponge transfer sufficient lube to do the trick. Only do 10 pellets of each of the three best-performing weights.

I then shoot 10 shots using one group and record the results. Then fire 5 un-lubed pellets through the gun before shooting the next 10 best performing pellets. Repeat this until you have fired all 30 lubed pellets followed in-between each group with 5 un-lubed pellets. You should see a difference in grouping at this stage and if you don’t, then repeat the process using a different lube like a varying viscosity of silicone.

You can actually buy pellet lube, with 2 customers of mine in Brisbane, Tony and Allan, swearing by it. Below are 2 sets of images before and after with lube on the pellets much like I have done above but using a branded pellet lube called Napier Pellet Lube. There are others and a Google search will identify them but getting them here in Australia is another issue. You need to follow through if you are into improving accuracy in an air rifle that does not perform.

Pellet Group Unlubed 01

Unlubed Shots

Pellet Group Lubed 01

Lubed Shots

Pellet Group Unlubed 02

Unlubed Shots

Pellet Group Lubed 02

Lubed Shots

Target Images Courtesy of Allan Ruffolo, Brisbane, Qld.

Pellet Lube for tuning air rifles

Napier Pellet Lube

The next step

OK, so if you have followed this process up to this point, you should have increased the accuracy of your air rifle by some small margin. Now if you want to go further and tighten the group some more, you need to alter your pellet speed.

This can be done by first stripping the air rifle and adding some shims to the spring and then firing 3 groups of your best-performing pellets with the best performing lube (or no lube as the case may be). If the groups tighten, then add another couple of shims and so on. If the groups do not tighten or in fact get larger, then you need to remove any default shims that are in place and reshoot the gun. When you run out of shims you will need to shorten the spring bit by bit or replace it with a softer spring. This is where a lot of air rifle accuracy problems start and end.

I have had to take off 1½ coils on one gun I tuned to bring the groups down to a competitive level, so you can now see that guns, springs, barrels and pellets etc., all vary considerably. The reduction in spring pressure obviously reduces the pellet speed, but more importantly, it reduces the recoil too, hence the addition of spring guides in tuning kits. There are exceptions to this, as in all spring gun tuning. I have cut off 2 coils on a spring and the pellet speed increased! The accuracy also increased, why? Most likely the spring was too long to begin with and was spiralling when under compression. Reduce the spring length and you reduce spiralling under pressure, hence you increase the efficiency and spring rate.

You need to record the weather temperature and humidity if you want to get really serious here as humidity and temperature play a big part in pellet performance.  Now I can just hear the ‘naysayers’ rumbling in the background. Well do this if you do not believe me:

  1. Record your best consistent grouping along with the ambient temperature and humidity.
  2. Then on another day when it is either hotter or colder shoot the group again with the same pellets. Point made.

We have found that when you sort your pellets into 5 groups after weighing them and final testing, that you get different results according to the climate. In fact, I have noted with one springer, on a cold day it performed better with a different pellet altogether. So, do not be surprised if you find your results kind of ‘fluid’ and forever changing, hence the need to document your tuning to make sense of it all so you can stay in front.

In another article, I will cover resizing pellets and give examples of temp/humidity changes to grouping results as this article is getting a bit long at this point.

Tuning Weihrauch air rifles summary

Before you race off and start tuning your air rifle, you need to be able to demonstrate to yourself that you are at least a fairly competent shooter. If you can’t hit a barn while standing inside one or your shooting is erratic at best, then no amount of tuning is going to help. Your air rifle should have a good quality scope on it like a Hawke Airmax or one of the up and coming MTC scopes, as these sights handle springers well. Those of you who are into tuning Weihrauch air rifles, you need to have a benchmark of what you are capable of doing target wise, PRIOR to embarking on an air rifle tuning exercise.

Author: Ian McIntosh, Gunroom

Target at 25 metres

Air Rifle Tuning to Stage 1

Air Rifle Tuning of the Weihrauch HW77, HW77K and HW97K models regardless of stock styles is the subject of this article. To avoid repetition of each model I shall use HW97K as the subject and the reader is to assume that this applies to each of the Weihrauch models above.

Vortek Tunining Kits

At Gunroom we stock a range of Vortek Air Rifle Accessories and Tuning kits for the HW97k and for some other Weihrauch models that are not the subject of this article. The kits are available ex-stock for fitting by the purchaser who has the competence to perform the basic swap out of the Spring and Seal kit after disassembly, degreasing and re-assembly, or alternatively, fitting by ourselves.

Doing it this way will save you some costs, but it is unlikely to give you the full performance that is available when the kit is installed by our-selves using the test sequences following. This is primarily due to the fact the installing the kit is only one factor in tuning your air rifle and even this has a number of variables, such as the number of shims you should install. Each shim will alter the performance to some degree and with every air rifle having a different DNA so to speak, you will soon see by the end of this article how many facets are considered when tuning an air rifle.

Weihrauch HW77KSE Air Rifle

HW77KSE Air Rifle with Hawke Scope

Air Rifle Tuning is not something that is done across the board with the expectation of getting the correct results: you need to tune for a specific regime, be it hunting where power is a major factor or target shooting where pellet placement is the key. In effect you can actually get a state of tune with your rifle that will give you good results in both hunting and target shooting but it won’t do both with top results, period.

Hunting requires an air rifle pellet to reach out over a greater range and at the same time carry sufficient energy to affect a high probability of a kill. This will generally mean that you need a FAC powered spring to achieve that energy and speed required.

On the other hand, target shooters will know that slower speeds generally mean more reliable pellet trajectories and pellet stability. Hence the use of softer springs of around 12 ft lb (16J) that provide better grouping using a slower speed. Vortek Air Rifle kits are available for this energy rating and even less for those requiring lower power levels.

As my audience is predominantly here in Australia, my focus is on what we use here as we are not as restricted as the guys in the UK are, yet….. In saying this however, the UK restrictions have created an air rifle fraternity there that has pushed the restrictive legal envelope to the max and as a result I am of the opinion that the UK air gunners lead the world in air rifle development. It is from their initiatives and development that I have taken the ball and run with it, be it in a different direction, but that is not by accident as we have different laws and shooting culture.

Air Rifle Pellets

The point that a lot of my clients miss is that regardless of how well your air rifle is tuned, without correctly matched pellets you are effectively only doing a half job. Tuning requires not only a balanced mechanism by way of a tuning kit, but matched pellets, quality optics, comfortable rifle stock that provides a comfortable posture when shooting.

To develop our air rifle tuning database we realised that as pellets play a major role in air rifles, that we would need to run comparisons against different pellet types and weights and different spring settings in the HW97K. It was also evident that while not all air rifles are equal, even Weihrauchs, not all pellets are equal either, even those out of the same tin.

So to set a benchmark with the pellets, all our research has started with each batch of pellets being weighed individually and those pellets that were not of the specified weight, either too light or too heavy, were discarded. The selected pellets then put through a “Go – No Go” gauge and inspected for deformity caused by packaging and travel in their respective tins.

I am not in a position to try every air rifle pellet made and so I have only researched the pellets that we sell and that equates to 22 styles of .177 pellets and 18 styles of .22 pellets. Now I am sure that somewhere out in the world there are other pellets that may just well be better than the top rated pellets we have following our tests. That being the case, for you guys who live and breath pellet architecture and performance, just send me a tin of what you want tested and I shall put it through the following regime and it’s performance will then be documented against the air rifle pellets we are currently testing. No cost as we all will benefit.

Weihrauch HW97K Air Rifle

HW97K Air Rifle on Blue Laminate Stock

One should also note that a specific pellet performance that we document in the HW97k testing does not necessarily mean that you will get exactly the same performance in your air rifle, though I imagine it would be close. It is for this reason that when we tune an air rifle, we can start off with what we have documented in performance over testing 1000s of pellets and tweak the spring to gain the best results from our best performing pellets. Unfortunately, those of you tuning at home, unless you have a lot of time on your hands to run comparisons, are likely to fall somewhat short of what can be achieved from your air rifle.

Basic Tuning of Air Rifles

We do 2 types of air rifle tune presently, one being a Basic Tune and the other a Stage 1 tune. The Basic Tune is what we give our clients who want a Vortek Tune kit fitted with a new air rifle purchase and that is done for the pricey sum of $60 that includes some selective pellet selection based on our on-going research. We do a maximum of 2 spring shim adjustments dictated by Chronograph readings and resulting groups.

In fitting the Vortek tuning kit we dis-assemble the air rifle and degrease it thoroughly then assemble it with the addition of polishing the sears and resetting the trigger pull if it falls below the legal limit of 1Kg here in Australia.

Depending on what the client has specified as the use of the air rifle, will dictate what pellets we select to set up the tune and resulting test firing at 20 metres. Occasionally, we get an air rifle that does not follow the normal pattern of HW97K and we end up matching it with a different pellet than what one would have expected.

Stage 1 Air Rifle Tuning

Stage 1 Air Rifle Tuning

Here we start off with what one expects of a Basic Tune with the following additions:

  1. The main spring is stone polished at each end to reduce recoil friction.
  2. The trigger group is specifically cleaned and lubricated.
  3. The trigger sears are more highly polished.
  4. The spring is fitted with no spacers initially.
  5. We then test fire 10 shots using each of the top 5 preselected pellets into targets set at 20 metres (50 shots). The pellets may change over time as we update our database* continually with on going testing.
  6. The air rifle is then stripped down and 2 washers at a time are added and the process repeated.
  7. From our recordings we will select the best spring spacer results and from those results we will have the best 3 pellet types.
  8. We will then subject these 3 pellet types to tests on targets out to 20 metres, recording MPS/FPS, energies and groups at each 10 metres using a Chronograph.
  9. The Stage 1 tune is a protracted tune requiring the firing of approximately 300+ pellets and it takes around 6 -7 hours. Cost is $260 with a $30 discount if the air rifle has been purchased through us.

*Our Database is currently being built where we have outputs from a large number of rifles, the pellets mentioned and 6 set distances that have provided data such as grouping, trajectories, speed, pellet decay etc. This has been set up to help us reduce the time spent shimming and testing where we can jump forward to a specific result and start there. While the results do vary, at least we will be close to what the final settings are likely to be.

It should also be noted here that piston seals do bed in and a few thousand shots down the track and the owner should chronograph the readings and if they have altered to any degree, call me so I can advise on a washer or pellet selection change from data collected initially.

Testing Equipment

The 2 Chronographs are Competitive Edge Dynamics (M2 Chronographs) with Infra Red Screen Sets.

The Decibel readings are from a Digitech Sound Meter.

Trigger Pull is recorded by Lyman Trigger Pull Gauge.

One should take into account that all the readings are comparative to each other and as more test results are filtered in, the readings will marginally adjust as the deviation is reduced through multiple recordings.

Over time we shall be posting graphs and charts depicting air rifle pellet performance, speed, energies, standard Weihrauch outputs including grouping, Vortek test results, range grouping, trajectories, noise levels with different pellets and power levels and anything that we can glean from the testing.

We will then start testing the HW100 series followed by other manufacturers PCPs.

HW100KT Laminated with Hawke Scope

HW100KT PCP Air Rifle in Laminate

Air Rifle Tuning Summary

This article just touches on what is being undertaken to help those of us who are looking for better air rifle performance without the bullshit that flows through this industry from unqualified and sometimes highly inaccurate forum writers.

I am open to suggestions and dialogue with regards to providing more information on this site, just tell me what you want to know and we can take it from there. Email me or txt me and I will call you back.

V-Mach V-Glide Kit

V Mach V Glide Kit

Remember, if you have a particular air rifle pellet you would like to see up against the likes on H&N and JSB, just send me a tin of at least 500 pellets and I will run them through our system and tell it like it is without the bullshit.

Already with the testing we have done it has shown very positive results for several pellet types and has shown some of the more popular pellets are not as good as some people believe they are. On the down side for me, once I publish the pellet reports and charts, I can see that I am going to be left with a number of pellets on the shelves, that is the crappy ones which don’t perform and there are quite a few of them.

JSB Exact Jumbo Monster Air Rifle Pellet

JSB Exact Jumbo Monster Pellet

Those of you who want a Weihrauch air rifle tuned, please take the stock OFF the rifle and just send me the mechanism by registered post unless you are in NSW, then you will need to get it freighted to me but please call me first.

OK guys, that is it for now and as I document the results on this site, I will add more type specific articles relating directly to charts and graphs as we put them up. So for you Weihrauch air rifle owners, now is the chance for you to contribute input for what information you would like to see come out of this air rifle tuning research, just get back to me.

Weihrauch HW100S

Weihrauch Spring Air Rifle Tuning Basics

Being a Weihrauch air rifle stockist and a keen owner of some of their air rifles, I have taken to air rifle tuning of Weihrauchs specifically in this article only. Presently I do not have the time to source parts for other brands and to learn the different idiosyncrasies of different air rifles. There is still plenty to learn about Weihrauch air rifles.

Weihrauch HW97K Air Rifle

Weihrauch HW97K Air Rifle

I am fielding calls about our database of pellet and Weihrauch functionality and comparisons almost daily, so in this article I hope to answer some of your questions.


Before you go ahead and decide that your air rifle needs tuning, you need to establish that you have done and are currently doing everything correctly. If not, then no amount of tuning is going to provide better results for you and you will have wasted your money.


Baracuda Hunter Air Rifle Pellet

H&N Hunter Air Rifle Pellet

Firstly, look at your pellet selection and pick a pellet that you feel gives you the best results. If you are using budget priced pellets then it maybe pertinent to invest in a higher quality pellet and track any improvement in your grouping.

Such a pellet should be something like the H&N Baracuda, H&H Baracuda Hunter or the JSB Exact Jumbo Heavy pellets. There are also undoubtedly other high quality pellets that will provide consistent accurate grouping.

Such a pellet should be something like the H&N Baracuda, H&H Baracuda Hunter or the JSB Exact Jumbo Heavy pellets. There are also undoubtedly other high quality pellets that will provide consistent accurate grouping.


The next thing I would be looking at is whether you are experiencing any parallax error through your scope. For those of you new to this, parallax error is when you view your target through the scope and the reticle ‘moves’ side to side or on and off the target when you move your head side to side. In fact, what should happen is that the reticle should remain steady on the target even when you move your head side to side.

Hawke Scope 3-9 x 50 AO

Hawke 3-9×50 Scope

Causes of this are usually due to the setup of your scope being incorrect. Short story is to get your eye relief sorted so you are in a comfortable position with your scope and then adjust the eyepiece so you are fully focused on the reticle with no blurring.

Then adjust your Adjustable Objective (AO) to give you the best focus of your target and this will eliminate any parallax error most of the time. Should you have a scope with a fixed objective and you still have some parallax error creeping in, then please contact me and we can work through it together. I will do an article on parallax error down the track a bit – just remind me.

There is one thing that needs pointing out here and that is the distances stamped on the Adjustable Objective. These are a guide only and help in range finding, however, should you be shooting at 20 metres, don’t expect the AO to be exactly on 20 metres. It will be close but not necessarily exactly right on the money. So if you are experiencing some parallax error adjust for clarity and focus rather than using the setting on the AO.


Quite often a guy will come to me saying that he can’t hit poop with his air rifle because it shoots like crap – no pun intended, just trying to be polite here. When asked to demonstrate this for me I have noticed on occasions that the shooter has to crane his neck at an awkward angle, lean forward or backward with his head and then crouch over the gun. He ends up looking like the hunchback of Notre Dame. No wonder he can’t hit anything and no amount of tuning is going to help him.

It is extremely important that the scope height and eye to scope distance is set up correctly for you; so that by just swinging the air rifle up to your shoulder is all that is required along with a slight head tilt. You need to get this part right so that muscle memory kicks in and you don’t need to re-establish your posture every time you want to shoot as this will save you “re-inventing the wheel.”


As the reader you will know that I live in Queensland, Australia, and here we have a firearms regulation that prohibits trigger pulls of less that 1kg unless you are shooting in a specific target shooting regime. That said, I reset the trigger pull of each air rifle I tune here down to 1kg though better results are often achievable with lighter trigger pulls of around 600 grams a lot of the time (I didn’t say that…).

This brings me to the point of setting your air rifle trigger pull into the realms of getting the right ‘feel’ and knowing just when it is going to shoot. I have had trigger pulls here of 3kgs and unless your name is Arnie, holding on target while squeezing the 3kg trigger is not going to be easy. So prior to deciding on whether your gun needs tuning make sure that your trigger pull is not causing your poor grouping.

Weihrauch Air Rifle Trigger

Weihrauch Air Rifle Trigger

If you don’t have a Trigger Pull Gauge you can get close using a vertical lift off the trigger lifting a known weight. Go onto You Tube and search there and you will find several ways of calibrating your trigger pull. The Weihrauchs have the Rekord trigger which is very reliable and easily adjusted with a nice feel.

I can provide 3 different types of triggers for all the Weihrauch air rifles, from ‘Straight Triggers’ to ‘Extra Set-back Triggers’ in alloy, black anodised and brass along with 3rd party trigger guards.


So we are back full circle with regards to air rifle tuning. The bottom line is that if you are buying a new Weihrauch air rifle then I recommend that you get a kit fitted. Furthermore, if you let me know what you intend to use the air rifle for, I can specify one of several pellets and tune the rifle for that specific pellet as no air rifle tune covers all pellets.

With a Vortek tuning kit fitted with the default shimming (Basic Tune) you will still have a formidable air rifle with a more controlled recoil and better accuracy. For those of you into hunting where you have to reach out further or if you are an avid target shooter, then a Stage 1 tuning kit will benefit your air rifle the best and help give you the grouping that you need.


So we are back full circle with regards to air rifle tuning. The bottom line is that if you are buying a new Weihrauch air rifle then I recommend that you get a kit fitted. Furthermore, if you let me know what you intend to use the air rifle for, I can specify one of several pellets and tune the rifle for that specific pellet as no air rifle tune covers all pellets.

With a V-Mach tuning kit fitted with the default shimming (Basic Tune) you will still have a formidable air rifle with a more controlled recoil and better accuracy. For those of you into hunting where you have to reach out further or if you are an avid target shooter, then a Stage 1 tuning kit will benefit your air rifle the best and help give you the grouping that you need.


In the past I used to do air rifle tuning by trial and error and by swapping out springs and cutting off coils etc., very primitive indeed even though I ended up with some good performances in the end. However, it is now 2018 and time is money and so I have taken it on myself to build a Weihrauch Air Rifle Tuning Database whereby I can fast forward and go into specific pellet and shim selection at a glance.

This has meant shooting 1,000s of pellets through both .177 and .22 Weihrauch HW97K, HW77k and HW77 models at distances of 10, 20, 25, 30, 40 and 50 metres all from a bench rest bag. I have done this using my own rifles and those of several of my customers. Namely I wish to thank Mr. Mike Schifilliti of Adelaide and Mr. Kurt Carmichael of Townsville who allowed me to use their Weihrauch air rifles as comparison rifles in building the database which is still under construction. In doing this I have recorded the following into the database:

  1. Standard Deviation at the barrel and at the target.
  2. Highest velocities at the barrel and at the target.
  3. Lowest velocities at the barrel and at the target.
  4. Extreme Velocity Spreads at the barrel and at the target.
  5. Average velocities at the barrel and at the target.
  6. Pellet energies at the barrel and at the target.
  7. Groups.
  8. Decibels.
  9. Pellet speed decays.
  10. Pellet trajectories.
  11. Pellet to Pellet comparisons using 16 x .22 Pellet types and 20 x .177 Pellet types.
  12. Barrel Velocities over 1000s of pellets (spring conditioning, seal setting and bedding in)

When all the data has been entered into the database it will allow me to tune most spring powered Weihrauch air rifles more accurately and quickly and to a specific pellet.


While I would like to tune every Weihrauch air rifle I sell it is not always warranted and will say this to you: if you only want an air rifle to control vermin, do some casual target shooting or plinking, then the Weihrauch air rifle is plenty good enough.

However, if you are target shooting seriously or into hunting whereby you need to reach out more accurately and further, then do yourself a favour and get your Weihrauch air rifle fitted with a Tuning Kit. That will reward you with better handling characteristics, smoother recoil, better grouping and ultimately better air rifle longevity.

Author: Ian McIntosh, Gunroom