How long can you leave a CO2 gun charged?

This report covers:

• The question
• Bulk-fill
• CO2 cartridges
• The deal
• Not the full answer
• The Komplete
• Summary

Today’s report is an answer to a question reader Decksniper asked recently. Let’s read what he said and I will take it from there.

“Do you or any reader who has tested it care to share their opinion on leaving an unspent CO2 cartridge (88 mm) in a Umarex Komplete air rifle?”

“It is well known that this rifle is actually dual purpose in being able to shoot with either nitrogen or CO2. Ham [Hard Air Magazine] review tests prove it and I use both in my Komplete .177 and .22 calibers. Accuracy is equivalent at reasonable ranges but velocity is far greater using nitrogen as expected. But CO2 delivers an incredible number of useful shots before a cylinder is exhausted. This lowers the cost of shooting to being very reasonable.”

“This gets back to my question. It isn’t practical for me, at least, to shoot 120 to 150 shots with any gun in one outing. I have too many airguns demanding their turn too. I’m hoping the greater hammer spring tension designed for nitrogen offsets the need to remove the CO2.”

The question

The question is—How long can you leave a CO2 gun charged? The answer is—it depends. In today’s report we’ll look at what it depends upon.

Bulk-fill

Sometime in the middle 1990s I bought a Crosman 111 CO2 pistol at a flea market. The lady I bought it from didn’t know how long it had been in the family. She said she found it in a drawer and I think she said it belonged to her late father. As far as she knew it hadn’t been touched in at least 20 years. It came to me in the original box and had the manual and the model 197 ten-ounce gas tank.

Crosman’s 111 bulk-fill CO2 pistol held gas for decades!

I took it home and went to my basement range where I immediately dry-fired it to see if there was any gas left. There was so I loaded .177-caliber pellets and shot about 30 shots before the power started dropping off. I refilled the gun from the tank that came with it. In all I fired several thousand shots before needing to get the 10-ounce tank refilled. The pistol got about 70 shots per fill, so it was about half-filled when I got it — after at least 20 years.

CO2 cartridges

Why then do companies warn us to not store our gas guns with CO2 cartridges installed? Let’s fast-forward to the 1960s. Crosman was making lookalike gas guns like the 38C and the 38T revolvers. The way those guns were made they often required a short pipe to conduct the gas from the piercing pin to the firing valve. That pipe had ends that were prone to leak.

This schematic of a 38C/T valve shows the pipe mentioned above. It’s part 38-065.

The deal

So, if there is a possibility of leakage when CO2 is stored in a gun it’s recommended to not store it with gas. The other reason is safety, because anything that’s in the barrel can be propelled by the gas. It’s kind of a loaded gun!

The bulk-fill guns have a seal at the gas port inlet and of course the firing valve is entirely sealed. There is really no good way for gas to escape. Of course all seals fail in time, but bulk-fill guns usually hold gas for a very long time, as you read above.

Most CO2 gas guns that use the smaller 12-gram (and 8-gram) cartridges have pipes like you see in the schematic. That’s true for most guns but not for all. You have to check and see if yours does. And they nearly all have face seals that are thin and prone to tear and leak.

But what about the guns that use those 88-gram and larger cartridges? That’s what Decksniper is asking about. Back in 2014 I wrote about a Crosman 1077 that was converted from using 12-gram cartridges to an 88-gram cartridge—the exact thing Decksniper wants to know about!

My 1077 has an adapter for an 88-gram CO2 cartridge that Crosman used to sell. The round knob at the bottom shuts off the gas flow so the cartridge can be removed from the gun with gas still inside the cartridge.

Not the full answer

That conversion is no longer made. So what about 88-gram CO2 cartridge guns today? Can their cartridges be stored with the guns? And even more to the point, what about those Nitrogen cartridges? Is it safe to store the gun with them? Here is what the Umarex Komplete manual says:

“If you choose to store your airgun with a nitrogen cartridge in it, always store your airgun in a secure (locked) location away from unauthorized users and separate from ammunition.”

Umarex addressed the specific question and says that it is okay to store the rifle with the gas cartridge installed, as long as all safety precautions are taken.

The Komplete

I have an Umarex Komplete to test for you and if this question had not been addressed I would have tested it. But I would also have told you beforehand that the rifles that use these large cartridges, both CO2 and now Nitrogen, are built more like bulk-fill CO2 guns than like 12-gram cartridges guns. I would have predicted that it was okay to store the rifle with the cartridge.

Summary

I hope you now understand what “it depends” means, as an answer to today’s question. With this knowledge you should be able to figure this out yourself for each new gas gun you encounter.

The post How long can you leave a CO2 gun charged? first appeared on Pyramyd AIR.