So why do some of us still use old technology and continue to shoot our old pumpers and our spring piston guns? As I mentioned in Pt 1, shooting PCPs is a package deal. Buy a pump up or a piston gun, all you need to do is grab some pellets and you can start shooting. These traditional air guns have built in power sources. Not so with PCPs. The gun is only part of the package. You still have to buy the support equipment to fill a PCP gun with compressed air.
How do you fill a PCP? There are three ways. The first way is with a special hand pump that attaches to the rifle reservoir. (A bicycle pump is way too low on the psi for this work). The Discovery uses a modest in that it uses a 2000 psi reservoir. That means that I can use a pump that Benjamin offers for the Discovery. When my Disco drops down to its minimum 1000 psi, 50 pumps gets me back up to the 2000 psi max. To pump up one of our 3000 psi PCP rifle, though, would require 100 pumps and that's out of the question for us. Has to be a better way.
![Image](http://i63.tinypic.com/33blede.jpg)
There is. It's with scuba tanks, which we get filled by a local dive shop. This is probably the most common air source used in the PCP world.
![Image](http://i66.tinypic.com/33vkyfa.jpg)
The third and last way to fill a PCP gun is with an add on compressor, called a shoebox compressor, which boosts the pressure capability of a standard shop compressor. No, a standard shop compressor by itself won’t even come close to such pressures needed to fill a PCP, but you'll still need a shop compressor to go with your shoebox compressor.
Note that none of these fill options are cheap. The Discovery pump, the cheapest option, runs about $200. The scuba tanks we got used, but we still had to spend money to have them certified and the certification runs for about five years. Dive shops rarely consent to filling a tank that is not certified and, even then, some shops won't fill tanks for air gun use. We have about $400 invested in scuba tanks. The shoebox compressor option is way more, so not a lot of PCP shooters use this option.
How many shots does a gun get one one fill? This depends on the volume of the tank, the psi rating of the tank and the power of the gun. (Note that most high end guns have adjustable power setting, so the number of shots will depend on the setting. On the Disco, the power is set, no adjustment.) The Disco uses a low volume tank that runs at a modest 2000 psi (most PCPs run at 3000 psi.) This makes it an easy gun to fill with the pump. It also makes it a gun that only gives me up around 25 shots before I need a refill and only 15-18 of those shots will be in the sweet spot psi range where velocity is fairly constant. Above or below this sweet spot, I will get changes in velocity and therefore changes in POI.
On our larger Daystate CR-97 PCP rifle with its large 3000 psi reservoir, I get 40 good shots. Some rifles now use even larger reservoirs at even higher pressures and can get up to 80 shots.
![Image](http://i66.tinypic.com/3zjv9.jpg)
When we get to the very top of the PCP rifle heap, we get rifles that are some of the most sophisticated rifles in the world, complete with regulators that guarantee exactly the same velocity with every shot, regardless of the psi of the tank, computers with LCD screens on the gun that tell you how many shots are left, electronic firing controls and much more. Needless to say, these are very pricey guns running into the thousands of dollars.
So why do most of my PCP guns mostly collect dust, even though I have the means to fill them at hand? It's mostly my personality. When I shoot, I don't want to worry about the number of shots I have left. I don't want to have to check the pressure in the reservoir. I don't want to interrupt my shooting to go refill the gun. Just not my style. When I shoot, I want my mind totally clear to concentrate only on my shooting. Since I don't hunt, I really don't need PCP power. Since I don't compete, I don't need a PCP and, now that I have mastered the technique of shooting piston guns, PCPs really don't offer an accuracy advantage, anyway.
This is an important thing to consider before you invest in PCPs. They may be a goof fit for you and they may not. As I said, going PCP is more than just an investment in the gun. For some, this is a perfect solution for their shooting. For others like me, it is not. Either way, though, no denying that these are awesome rifles.