In this article we are going to look at how to fill your PCP Airgun. This can be a little confusing and overwhelming for those not accustomed to the process.
One of the most asked questions I get, deals with how to fill PCP, which stands for Pre-Charged Pneumatic. Before we just jump right in, let’s briefly talk about what is a PCP rifle. All guns require some sort of energy to propel their projectiles. Some guns use a spring, some use co2 gas, others use compressed air. PCP airguns use compressed air which is stored in a reservoir on the gun. This differs from other single pump or multi-pump airguns in that there is a large volume of “Pre Charged” air which allows for multiple shots between fills. PCP Airguns generally represent the top of the airgun food chain for power and accuracy.
So how do you get them “charged.” That is the big question everyone always asks. PCP guns are generally more expensive already, then there is the challenge of how to fill them. One thing I want to mention right up front. I get asked this all the time; “can I fill my PCP gun with a shop compressor.” The answer is simply no. Your shop compressor tops out at about 150 psi. Most PCP guns run on 3000 psi. So you are WAY short of where you need to be. So how do you fill your PCP guns? Let’s take a look at some options.Air Venturi PCP Hand Pump
The least expensive way to fill your PCP airgun is to use a simple hand pump. There are several different manufactures out there. Essentially it looks and works very much like the old hand bicycle pump. Some come with a standard female 1/8 bspp end that is compatible with most airgun fill probes or connectors, others may come already equipped with a female, foster quick disconnect fitting. If you would like to use your hand pump to fill multiple guns quickly and easily, I suggest that you equip it with the female air venturi quick disconnect fitting if it’s not already so equipped. From there you can make just about any fill probe or adaptor compatible by adding the male quick disconnect end to them.
Now each gun is going to be different.. but you can bet that it will take about 10 strokes or more to raise the pressure in your gun by 100 psi. So you can imagine that it can become hard work very quickly. Another thing to consider with a hand pump is that you need weight/mass not just strength to get up to 3000 psi. If you don’t weigh 200 pounds or more, you may not be able to get past 2400 to 2500 psi.Scuba Tank
So what are the other options? The most practical option is to use a scuba tank. Most scuba tanks fill to 3000 psi and store 80 cubic feet of air. That is a lot of air.. Generally they will have what’s called a “k-valve” but some tanks may also have other types of valves such as a Din valve. Others may have a combo valve that has an insert that converts the din valve to a k-valve. Since the most common valve is a k-valve, we’ll look at how to put one to work. This is a standard 3000 psi, 80 cu, aluminum tank and it sells for around $200. I’ve seen some tanks out there for less, but make sure, especially if you are looking to get a used tank, that you get one with a fresh hydro and visual inspection. These have to be current or the scuba shop will not fill your tank.
eBay is a place most people ask me about and on occasion you can find a good deal. Most of the time the tanks are older and in need hydro testing and visual inspection. This can run $50 to $75 so, be careful when you go looking at used tanks. The best place to find a deal is a local scuba shop. Our local shop sells used tanks for about $150 ready to go. It’s a great, reliable way to get what you need safely and ready to roll.
Once you have your tank, you need something to go from the tank to your gun. I have this scuba tank adapter here that has a k-valve on one end and a female 1/8 bspp connector on the other end. Like the hand pump, this is the most common connector and should take most probes and fittings. I prefer to fit mine with a quick disconnect fitting so that I can quickly fill multiple guns. This setup, with the quick disconnect, runs about $120. I know this adds a lot to an already expensive airgun, but once you have it, you are all set for just about any pcp gun out there.Female quick disconnect fitting
I’ve been able to get about 10 to 15 usable fills from my 3000 psi tanks. I say usable, because after the first few top-offs, the scuba tank’s pressure starts to drop below 3000 psi so subsequently you don’t get a full charge in your gun. Each gun will be a little different. My Benjamin Marauders does really well between 1200 and 2600 psi, so I get a lot of fills from my tank. Once my scuba tank drops below 2400, I set it aside for my next trip to the scuba shop.
So we’ve talked about it, but how do you do it properly. I’m talking about adding the quick disconnect fittings, or for that matter, the factory fitting to your fill device. It’s pretty easy, but you will need a few tools and some supplies. First you’ll need some plumbers tape. This stuff is PCP gold. It is available at just about any hardware store and it will become your best friend. Next you’ll need some wrenches and possibly a small vice. I like using a small vise, because it is the 3rd hand I always wanted.Male foster quick disconnect fitting
So with the hose firmly in the vise, wrap the fitting with 3 or 4 layers of plumbers tape and begin to screw it in. Once you’ve gone as far as you can by hand tightening, get your wrench and finish off the job. You want to make sure that this is tight, not so tight as to break things, but tight enough to do the job. If you are concerned, just take your fittings with you to the scuba shop and they should be able to get you all set.
To add the male end to your rifle’s fitting, you’ll do the same procedure. Here is a typical probe fill adapter. It’s setup to go right onto the hose, but we can also add this male quick disconnect fitting and now it will go with any of our fill devices.
Regardless of which method you choose, it all comes down to finding the most efficient, convenient and cost effective way to fill your airgun. By utilizing the quick disconnect system, you can setup just about any fitting to be compatible. This makes it really easy to use 1 fill system for all your guns and will work with either a hand pump or scuba tank fill system.