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.
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.
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:
- The main spring is stone polished at each end to reduce recoil friction.
- The trigger group is specifically cleaned and lubricated.
- The trigger sears are more highly polished.
- The spring is fitted with no spacers initially.
- 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.
- The air rifle is then stripped down and 2 washers at a time are added and the process repeated.
- From our recordings we will select the best spring spacer results and from those results we will have the best 3 pellet types.
- 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.
- 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.
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.
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.
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.
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.