Shooting airguns at altitude
by B.B. Pelletier
A lot of you asked for this report but Jay was the first. As we drove from Texas to Las Vegas and the SHOT Show, we passed through several communities higher than 5,000 feet, and my appreciation for how widespread this problem is certainly increased. We think of Denver as the mile-high city, but there are plenty of smaller cities that are even higher, so knowing something about how airguns perform at altitude is important.
When we published The Airgun Letter, one of our readers, airgun dealer Howard Montgomery, did a test of spring guns, CO2 and multi-pump pneumatics shot at elevations ranging from sea level to 8,500 feet. He based his tests on another earlier study done years before by airgunner Ron Balbi.
Howard used the following guns:
RWS Diana 36 in good shape (.177)
Webley Hurricane pistol in good shape (.177)
Crosman 1377 in good shape (.177)
Crosman Mark II in good shape (.177)
Both an Oehler 35P chronograph and 2 Chrony F1 chronographs were used. The light pellets were RWS Hobbys and the heavies were Crosman 10.5-grain Premiers.
Howard also provided a test from Ron Balbi done years earlier and archived by airgunner Steve Gibbons. The guns used were:
FWB 124 (.177)
RWS 45 (.177)
Beeman R1 (.22)
So, the trends operate as shown. If you do your own test today, you'll get different results, but the relationships will be similar. Remember, temperatures below 50 degrees F will affect CO2 guns and temps below 20 degrees F will start to affect spring guns. Also, note that as the air thins at altitude, a gas gun can go faster. PCPs were not tested, but they should improve at altitude.