PCP Compressors for your pneumatic air rifles.

Electric PCP Compressors for filling your pneumatic air rifles are steadily gaining traction amongst air rifle enthusiasts Australia wide. With the prices that are lower than Carbon wrapped Scuba bottles in some cases, it is a no-brainer to opt for an electric high-pressure compressor for your PCP.

In this article I will lay bare the pros and cons associated with buying one of the Chinese compressors and what I would expect you to get from the experience. I will discuss only one model here, but you can apply most of what I will show you to other small PCP compressors. Note: when I talk about small PCP Chinese compressors, I am referring to the units that you can buy direct from China for under $500 – believe it or not, the freight costs more than the compressors.

Hand Pump close up

Hand Pump

Hand Pumps and Scuba Bottles.

Going back a few years, if you had a PCP (aka Pre-Charged-Pneumatic air rifle), you had to charge the air rifle reservoir with either a hand stirrup pump costing $300 – $450 or decant the air from a Scuba bottle.

The hand pump was and still is the hard way of doing anything, I even get a sweat looking at one. Constant use of the Hand Pump and you will find you have muscles where you would least expect them. The leading hand pump several years ago was the Hills pump out of the UK, but it has recently been eclipsed by Chinese hand pumps at as low as 1/6th the price of the British unit. Of course, there are those of you who will say, “I would prefer to buy British as they are better than the Chinese models”. Well that is debatable, but if I had to revert to a hand pump, I would rather buy 6 units for the same money as 1 UK hand pump. Having worked on both the British and Chinese hand pumps, I will say this, there is very little to choose between them now.

Next option was the Scuba bottle in either 232 Bar or 300 Bar. The 232 Bar is the most accessible Scuba bottle second hand and priced anywhere from $50 upwards. The problem with these 232 Bar tanks is that most PCP air rifles now run on 240 Bar and hence you don’t have the pressure to fill one to capacity. The 300 Bar tanks are a lot more suitable, offering quite a few fills dependent on volume but these bottles cost a heap more than the 232 bottles do.

Cons:

  • Bottom line guys, you cannot put more air pressure into your PCP than is in the Scuba bottle,
  • you are tied to the mercy of a Dive Shop for filling,
  • many dive shops do not have the capacity to fill to 300 Bar,
  • there are not too many dive shops out in the country,
  • there are the costs of filling and having the bottle tested regularly,
  • the aluminium and steel scuba bottles are heavy while the carbon wrapped bottles are light but very expensive.

Pros:

  • The Scuba bottles are very portable and suitable for trips to your club or to go hunting.

High Pressure PCP Compressors, are they really the answer?

As PCP air rifles require air pressures ranging from 200 Bar (2,940 psi) to 300 Bar (4,410 psi) you need a 3 or 4 stage compressor to attain that degree of air pressure. That is where we get the term High Pressure Compressor from when discussing filling Scuba bottles or PCP air rifles.

For this article I am staying with the Chinese PCP Compressors pictured and am in no way referring to the likes of (say) Bauer High Pressure Compressors as the two are worlds apart in performance, cost, duty cycle and longevity. Having owned a Dive Shop for years when I lived in Port Hedland, I owned 2 Bauer Compressors for filling Scuba bottles where we filled hundreds of bottles a month in the heat and humidity. I have a fair idea what I am about with High Pressure Compressors as we apply them to PCP air rifles.

Cons:

  • With the electric compressors you need 240 volts and that is not always going to be available when hunting or when visiting small bush shooting clubs,
  • You need at least 20 but preferably 40 litres of cool clean water to cool the compressor,
  • These Chinese units do not have a very high duty cycle, in fact I would NOT recommend running one continuously for more than 30 minutes,
  • The water trap is hardly what I would call a trap, having an absorbent filter no bigger than a tampon, (did I say that?….)
  • You cannot walk away and just leave the compressor running (as I will explain later).

The Pros:

  • No driving to and from a dive shop getting your Scuba bottle filled, you can now fill at home,
  • Running costs are negligible,
  • Fairly portable providing you can source 240 volts and water,
  • Cheap.

Buying from China direct.

Those of you who want one of these Chinese High-Pressure PCP Compressors can buy direct, paying anything from $460 to $700 depending where you source one from. The gamble you take is warranty, as there are NO compressor agents in Australia that I know of and given the nett price of the compressors (excluding freight), finding someone who can repair it for less than a new one would be difficult. I wish you luck.

I am bringing them in with bulk buys, marketing to my PCP customers of Gunroom only as I am not making a profit and only providing a service by supporting customers that support me. The compressors cost me $460 landed here, I then must pay 10% GST, $20 for synthetic oil, pull the compressor down and do 3 modifications and then test them. The $50 that I put on each compressor taking the retail to $580 including GST, barely covers my time making the modifications and on top of that, I must warranty the units. So, you see I am hard pressed risk wise with warranty and so this compressor is only available in a package price with a rifle or direct to a customer who has purchased one of my air rifles previously.

PCP Compressor strip-down

Modifying The Compressor

To understand warranty with regards to firearms and the like, we only get the faulty parts replaced and must pay the freight (chargeable to the customer) and do the labour at our cost. Yup, that is correct, we need to factor in our anticipated labour costs into the margin.

Running these PCP Compressors.

I have said this already, but I cannot stress it enough, do NOT run the compressor for more than 30 minutes at a time. You must also dip your hand into the water tank and check the temperature regularly as these PCP compressors will get quite warm and become less efficient in hot weather.

With the humidity we get in places like Queensland, regular draining of both drain points is highly recommended while running the compressor. I leave these drains open when I have finished using my compressor to allow complete draining of moisture.

Do NOT attempt to fill a Scuba bottle with one of these small PCP compressors, they are not made for it. What I do, is I fill the rifle to be tested and that takes anywhere from 40 to 90 seconds depending on the residual air in the PCP if any, the outside air temperature, humidity, water temperature and air surrounding the compressor. I fill/top up the gun and then switch the compressed air valve over to my 300 Bar Scuba bottle which I run for 10 to 15 minutes or until the water starts getting hot. I do not allow the compressor to get over 75 degrees in head temperature: this is visible on the temp gauge beside the lifting handle.

Huma External Regulator

After filling around 10 PCPs over 2-3 days and adding 10-15 minutes of run time onto my 300 Bar tank, it is then full and can be used for quick fills should the need arise. I mainly use the 300 Bar tank to supply air at a regulated 240 bar air supply via a Huma regulator (inset) and a 2.5 metre whip lead plugged directly into a PCP for pellet testing at a set pressure for tuning air rifles.

So, should you buy one of the Chinese PCP Compressors for your PCP air rifle, I feel you will be very pleased with the purchase providing you follow my tips and try not to re-invent the wheel with the unit.

I have recorded the following fill times for your interest:

  • Brocock Compatto filled to 240 Bar from empty took 75 seconds, and from 50 Bar to 240 Bar took 45 seconds.
  • Brocock Bantam HiLite from empty to 240 Bar took 130 seconds.
  • Weihrauch HW110 from empty to 200 Bar took 58 seconds.
Brocock Bantam HiLite

Brocock Bantam HiLite

Running the compressor on concrete in the glaring heat of the day will provide longer fill times, while running in cool to wintry conditions will reduce filling times. Remember to keep an eye on the water temperature as this also affects the fill times. Do not walk away from the compressor while it is running as the water pump is only a fish pond centrifugal plastic unit and sure as shooting it will malfunction if you are not there to keep an eye on it.

Some guys are putting in ice to cool the water, well, if you do this you risk very chilly water hitting a very hot head and prompting damage to occur. I am not saying don’t put ice in the water to cool it, that’s ok in moderation like everything, but knowing some of the clowns that I know, they will overstep the mark for sure… Keep the water cool but making it cold on a sweltering day is not recommended. I can also supply a temperature gauge for the tank water should you want one.

As the air filter is basically non-existent, I am hopeful of sourcing a larger unit that can be retro fitted to the compressor for better filtration. Long whip leads, Foster fittings, BSPP adaptors and fittings are available ex-stock to suit these PCP Compressors.

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