What to do with fire extinguisher tank?

[PeteS]

I have an old fire extinguisher tank it was from a disposable powder type kitchen extinguisher. It is aluminum and it took about 675 ML to fill it. The cap is some kind of plastic that seems to be pretty tough. It had a hole that nicely took 1/4 NPT threads and it could probably be adapted to 3/8 NPT or maybe even 1/2 NPT threads.

I am torn on what to do with this tank. I figure it could be used a number of ways.
1. A piston valved pneumatic somewhere in the 22-50 caliber range.
2. A 50 caliber combustion.
3. A 50 caliber hybrid. This is probably my first choice if it will take enough pressure to make this a worthwhile choice.
4. Something else? I am open to suggestions.

I have no idea what pressure these tanks are designed to take. Does anyone here know? I will probably guess and then pressure test it before using it, but it would be good to have some idea of what pressure it is likely to be OK with so I don't destroy it by having unreasonable expectations.

EDIT: I am reading that these probably carry about 300 PSI when in their designed usage.

EDIT 2: Possible hybrid config:


EDIT 3: It does not have the tube to the bottom of the tank. That was a plastic tube in this case and was removed.

Pictures of the tank:

[finland66]

Semi Auto marble sniper and 300psi filled bottle in backpack.

[dart guy]

op, cartrige load, airsoft shotgun? but you may want a regulator so that you can shoot through aluminum when you want to, and also make it also harmless at other times.

[Zeus]

It's powder filled, which means it's nigh on useless for a HPA vessel. I believe (don't quote me) that they run at 170 odd PSI, tested to 270.

[hawktalk]

I had a metal powder fire extinguisher and i could get it up to 250 before my compressor packed up lol. the tank i had was rated 200psi (safe working temp) and tested 380 psi.

[Gun Freak]

I'm on board with Zeus. All the powder tanks I've seen have a working pressure of 120 psi and a test pressure of something like 360. I have tested them to 200 and use them routinely at 120, but I wouldn't have much faith in them for higher pressure applications. They're really not good for much more than a low pressure pneumatic.

[jackssmirkingrevenge]

They're really not good for much more than a low pressure pneumatic.

I would have no problem using this for a 5x hybrid, there is a difference between constant pressure in a pneumatic chamber and the pressure spike of a hybrid.

[PeteS]

Opinions seem to range pretty widely on what this tank might be used for.

I am not sure which way I will go. I'll have to mull it over a while.