There are basically two methods of filling, The first to look at is the high pressure handpump. The AXSOR pump that we sell is a three-stage handpump that looks a little like a bicycle pump but it is capable of producing 200bar. pressure [about 3000psi.]. Initial cost is $225.00 but from there on the air is free. The handpump is reasonably portable, it can be taken to the range, on airlines and you are totally independent with your very own air supply. The most important feature of the handpump, however, is that it lets you put exactly the same amount of air into your small cylinder each time. Filling from a SCUBA tank will not let you do this [explained later]. The rifle/pistol cylinder simply screws directly onto the pump and you go to work. There is a good quality pressure gauge on the pump that tells you how much air is in the cylinder as you work away. The high pressure that these pumps produce creates heat in the pump and moisture is squeezed out of the air. I have never found overheating to be a problem with the pump……only with me!! There is a drain cock at the base of the pump where excess water that has collected can be drained off. Rifle and pistol cylinders are made to operate on 200bar. pressure and a full cylinder is normally good for between 200 and 250 shots. The pump supplier advertises 4 to 6 shots for one stroke of the pump, this tells me that it takes about 50 strokes to fill a pistol cylinder and over 100 to fill a rifle cylinder. It’s a good aerobatic workout…..just don’t do it right before a match!!

Using a SCUBA tank as your prime source is a lot handier than the pump but it is more expensive, more dangerous, a lot more hassle and it doesn’t do the job that a handpump does. First you have to buy a SCUBA tank…..about $200.00 for a new one. Prices differ a lot on this item, so shop around. A SCUBA tank requires pressure testing periodically which is an additional cost. The dive shops will not fill them without this testing. Some [not all] dive shops require you to be a member of a dive club or have insurance before they will fill for you. You need to clear all of this with your local dive shop before you commit yourself to SCUBA air. After you have the tank you need a 200bar. DIN fitting in order to attach your adapter that came with your gun to the SCUBA tank,…..about $60.00. The SCUBA fill system is very convenient…..just screw your cylinder onto the tank and open the valve for a moment …..presto…..done.

Now for the downside of SCUBA filling; unlike CO2, the pressure in the tank will drop with each filling and so will the pressure in the small cylinder that is being filled. The pressure in your small cylinder will be less and less with each filling. The pressure that you will get in your small cylinder will always be the same as the SCUBA cylinder pressure…..there is no regulator between the two. Now, the pressure that the gun requires to fire the pellet is only about 5bar.[70psi] so as long as the cylinder has more than this in it there will be enough to accurately fire a shot. The main point to remember here is that you will never get the same number of shots with your cylinder after each successive filling because the SCUBA supply tank pressure drops. When your SCUBA tank gets down to 8 or 10bar. [120psi] or so, it is time to refill because it probably wont give enough pressure to finish a match. By the way, 1 bar. [one atmosphere] =14.69psi.

All of the safety precautions that we have written about CO2 applies to SCUBA air as well. The air system because of the higher pressures involved is even more dangerous. There are some who even claim that one must not use petroleum based oils or grease around high pressure air because a dieseling effect that could cause an explosion. It is absolutely necessary to regularly drain the moisture from the base of your handpump if you use one to make sure no moisture enters the small cylinder. There is not much evidence of corrosion from moisture yet but the aluminum cylinder is sure to corrode in time with the combination of pressure and moisture. We can inspect the air cylinders inside and detect any corrosion, the cylinder should be sent to us about every two years for inspection.

This chart shows the approximate number of shots available from various size SCUBA tanks when the tank is full.....bear in mind that a part-full supply tank will only yield a part full cylinder.