how to get constant air flow for bb guns

[darkpyro]

i am wanting to make a bb gun but do not know how to get the constant air flow and a do not want to be hooked up to a compressor the whole time im shooting please help me.

[beebs111]

u could use regulated co2 or a really big chamber pressurized up high thru a small nozzle

[saladtossser]

u would need 8 gal worth of 80psi air.
a 20oz co2 pb tank won't do the trick, a big chamber is a good idea.

[darkpyro]

how big are we talkin like 50cm long 80mm pvc pipe

[beebs111]

i wans thinkin one of those half scuba sized co2 tanks, and for the chamber about 6 foot of 6"pvc

[boilingleadbath]

Darkpyro:
There is a airsupply-on-board BBMG on this site; mr.Plow's "Vortex project". He has a chamber some 25% smaller than your 50x8cm chamber would be.

He says he gets roughly 100 shots per charge, which at typical rates of fire corresponds to roughly 1.5 seconds of firing.

[darkpyro]

okay ill have a look so if i only held the trigger for 3 miliseconds it would only shoot about 15 bbs right

[boilingleadbath]

No, if you held it for 3 milliseconds it'd fire 1/5 a bb - but that's not a valid excecize because:
A: you can't press the trigger for 3 milliseconds.
B: the chamber takes longer than that to pressurize

15bbs would be about 1/4 second.

[darkpyro]

alright then thanks for the help