TargetTalk

I shoot air pistol at home all the time. I usually use one of the three-stage manual pumps to refill my PCP cylinder on my Steyr LP10 when I'm done, but I happen to also have a high pressure nitrogen tank laying around for making nitro coffee or beer. That N2 tank is filled to about 170 Bar and as far as I know, has dry (no water vapor) nitrogen in it. It even has a DIN adapter on it.

Here's my question: could I safely use N2 to fill my PCP air pistol tank? I think the answer is yes? N2 density at 20C is about 1.16 kg/m^3, while air is 1.204 kg/m^3. Also, air is about 78% N2 anyway.

Follow-on question: what differences might I observe when shooting with N2 rather than air? I guess that difference between high pressure air and high pressure N2 is similar to the difference between one brand of pellets versus another. (paging Rover and William) Which is to say, almost imperceptible.

Thoughts? Am I going to blow up myself, my pistol, my dog, and my house if I try this?

You're right on all points. I've seen this question before, so you may wish to Search here.

I DON'T know what pressure they would refill your nitrogen tank to, so beware of that.

I always thought this would be a good idea myself.

I doubt it's dangerous, but I would imagine having pure N2, which would be slightly less massive than ambient air, would alter the acceleration profile of the pellet in the barrel, so you would have to make a sight adjustment.

I don't think it will be an issue. Standard pressure for a big tank is 200 bar, so it's safe in that regard. I coach at a college, and I've occasionally thought it might be easier to get a big nitrogen tank delivered through the chemistry department supply chain than to deal with going to the local SCUBA shop. However, we have at least three SCUBA tanks going at once to fill different brands of pistols, and you still have the problem of them being pretty useless once they get down below ~ 130 bar. If we put a multi-port manifold with different fill adapters on a big nitrogen tank, it wouldn't last all that long.

Rover, you're right on all counts: this topic has been covered before, and I ought to have used the search feature before re-asking. Thanks for the responses, all.

Our club for many years kept a large tank of nitrogen for air gun users. Since normal air is 79% N2 the only thing being removed is the oxygen- so no corrosive effect. We just treated it as if it was compressed air. No problems as far as I know.

Cheers. Dr Jim

Gwhite wrote: ↑Wed Dec 13, 2023 10:25 am I don't think it will be an issue. Standard pressure for a big tank is 200 bar, so it's safe in that regard. I coach at a college, and I've occasionally thought it might be easier to get a big nitrogen tank delivered through the chemistry department supply chain than to deal with going to the local SCUBA shop. However, we have at least three SCUBA tanks going at once to fill different brands of pistols, and you still have the problem of them being pretty useless once they get down below ~ 130 bar. If we put a multi-port manifold with different fill adapters on a big nitrogen tank, it wouldn't last all that long.

Just an fyi, the price of nitrogen, hydrogen, and especially helium has doubled/tripled since 2020. I get it, that the cost of helium is going up- it is a finite resource. But the other two? Price gouging, for sure. Tank rental has also doubled, year on year, since 2020.

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Just an fyi, the price of nitrogen, hydrogen, and especially helium has doubled/tripled since 2020. I get it, that the cost of helium is going up- it is a finite resource.
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Though it is manufactured in quantity in the sun