A small peristaltic pump would pump a reservior upto 1 or 2 bar quite easilly.
Or maybe use those little CO₂ that you can get for fizzy drink makers?

Del

You could try to rip apart an airsoft gun and use it's internals.

I would go with the CO2 cartridge so you don't need a pump as it will take quite a bit of power to make the air pressure and volume you need.

If you really want a pump onboard and since your into RC stuff, they sell very small CO2 powered model engines for airplanes. I imagine if you were to power the shaft of one of those with a motor, by playing with the valves, it could be modified to work like a pump.

Thanks so much! I never thought of using a disposable (or refillable) C02 cans! Those would be a lot better than what I was thinking. I think I just might join, this place is very helpful.

That's how it begins. Next thing you know you'll be waiting for a piece of a broken bath tub in the mail....as in here.

_{(it's a long story...literally)}

Ahhh, my desire to help exceeds the good judgement of keeping quiet. I don't know why I know these things:

There is a long running, quite advanced gun system in use for Radio Control naval combat. Yeah, I can hear the groans.

Start here or search up your own. There are links that will tell you how to buy, or how to build your own - but the long n short is quite effective remote control BB firepower.

I understand they USED to run compressors, but use co2 cartridges due to power limitations - they went through a lotta batteries. You may not have that problem.

Those wrist and arm blood pressure monitors use a battery powered compressor. I don't know if they put out enough volume or pressure.

Thats a good one. though you would have to concoct a storage tank and valve for discharge. Maybe a small check valve for back pressure.

I like the compressor from a BP unit though.