unfinished projects, your opinions? 6mm rifles

[TheNewKid22]

Happy new year guys javascript:emoticon(':)')

i'm doing some re-visiting to some unfinished projects from last year and i'm keen to get them finished but i've come across some things that i'm not sure about so i thought some fresh ideas would be able to help.

so far i've got 3 projects on the go:
semi auto 6mm gun i was thinking of doing a daystate airwolf style but as my firing chamber is 15cm x 2cm i was planning to mount two 24cm x 8cm on the gun itself but if i go that way (which i have all the parts for except the blow forward bolt) it will be very bulky an i'm starting to think if i cut those loose and have a separate remote resevour in a backpack or something what would you guys do? ( it would be interesting to see what sort of pressure drop this gun would have after each shot, how many consistent shots i would get before a refill?
at say 300-400 psi?)

single fire/ multi shot type pipe gun with a slide valve system with a manual realoading system( manual because i didn't want to have any power loss because of the blow ford system) does anyone know if or how much a blow forward system effects the function of the gun? this gun has a secondary of 24cm x 8cm and a firing of 10ml firing at 600psi, and finaly with this gun i have tried a few different trigger/ firing systems but cant seem to find one that works well any ideas?

lastly today i put together a torch coaxl gun thing so i will be very interested in seeing how that goes after the quick steel cures

thank you for any help or input you have its always very appreciated and makes the difference

[Dig_Gil]

600 PSI?! Are you sure? That's about 40 Bar! Do you know what that means? 40 times the atmospheric pressure! I doubt you'll have any significant problem with pressure drop with that kind of power. Get a long barrel handy.

For the bulkiness of it, I guess it's not bulky at all. The gun I'm building is about a meter and so long and the width (read "height") of an extended hand. I expect it to weight about 10Kg when finished (no really sure). With this said, I don't consider it bulky for a pneumatic rifle. Maybe more than usual, I don't know (never picked up a pneumatic rifle before). Rifles using the hammer kind of valve (like the Girandoni; http://en.wikipedia.org/wiki/Girandoni_Air_Rifle) are lighter and more compact, but about the same weight, I guess.

About the pressure drop and the shots you can trigger, here's the maths:

Consider using a reservoir filled at high pressure then attached to a regulator that closes it at a lower pressure, that fills a chamber (that if you use a Q.E.V.-like valve). The "ShotVolume" is the volume wielding that lower pressure.

For any pneumatic system: Pressure1*Volume1=Pressure2*Volume2
Therefore:
ShotPressure*ShotVolume=ReservoirPressure*UnknownVolume
Solving for that UnknownVolume:
(ShotPressure*ShotPressure)/ReservoirPressure=UnknownVolume
That is the volume of air lost in the reservoir for each shot. Now:
ReservoirVolume/UnknownVolume= Number of shots before all air in reservoir runs out. That is when reservoir pressure equals to shot pressure (correct me here if I'm mistaken).

Remember that this set up holds up while the reservoir pressure is over than the shot pressure (regulated pressure; lower pressure). That means you won't feel the drop in pressure until the reservoir is almost out.

[fenrir]

Any pics would help.