A question I get asked a lot, and one that
appears frequently on airgun forums, has to do with whether or
not a CO2 airgun should be stored with a
pressurized CO2 cylinder in it. My
response is based on 20 years of experience working with many
different types of CO2 airguns. What I
describe below has worked well for me and should work well for
the majority of CO2 airguns that you are
likely to run across.
manufacturer’s suggestions are mostly based on liability issues
related to leaving an unattended airgun “loaded”. A CO2
gun with a charged cylinder is dangerous, even if no pellets or
BBs are in the gun, due to the significant muzzle blast (the
blast alone can damage an eye or ear of an unsuspecting child or
adult). An airgun with no CO2 cylinder in
it is basically harmless. Therefore, the manufacturers almost
always recommend removing the gas cylinder at the end of each
For long-term storage (more than one
month), my recommendation is to always remove the cylinder and
to make sure the seals are kept lubricated (see recommendations
below). CO2 cylinders all differ slightly
in the shape of their tips and leaving a cylinder in a gun for a
protracted period of time can leave an imprint in the seal. When
a different cylinder is inserted, it might not seal properly due
to the impression left by the previous cylinder. I’ve purchased
numerous vintage airguns than have arrived with CO2
cylinders that appear to have been left in the gun for 10 or
more years. Many of these guns are still charged with CO2
and shoot fine. However, when the old cylinder is replaced with
a new one, most of these guns wind up leaking badly around the
seal. For example, I recently bought a Crosman 38T (.22) that
came with an old “bottle cap” style CO2
cylinder installed. Judging from the dirt and spider webs around
the cylinder and grip it looked like the CO2
cylinder had been in the gun for 15 – 20 years. To my surprise,
the old cylinder was still almost fully charged and the gun shot
fine, clocking .22 pellets at over 300 fps. When all the gas was
used up, I carefully removed the old cylinder and inserted a new
one. When the new cylinder was pierced, all of the gas rushed
out around the seal and no amount of Pellgun oil would stop the
leak. The gun was shipped off to have new seals installed.
So, here are my recommended steps for
preserving the longevity of the seals in CO2
- Place a drop of Crosman Pellgun oil
on the tip of EVERY new CO2 cylinder
installed in an airgun.
- Do NOT leave a charged CO2
cylinder in an airgun for more than about a month.
- When removing a cylinder that still
contains gas, slowly release the gas to avoid cooling the
seals too much (better yet, just shoot the gun until all the
gas is gone). A sudden release of gas can tear some seals.
- Do NOT over-tighten the CO2
cylinder in an airgun. Tighten it just enough to pierce the
cylinder and seal it, but no more.
- If you have a CO2
airgun that leaks, put two drops of Crosman Pellgun oil in
the cylinder seal area and let the gun sit for two hours.
Then, insert a CO2 cylinder and shoot
the gun to distribute lubricant to the internal seals.
Remove the CO2 cylinder and put the
gun aside for three or four days. About 40% of the time,
you’ll find that the gun will not leak the next time you use
it. If it does, it’s time for new seals.