SpudFiles

So here it is, i made a design, for a full auto BB machine gun, or whatever caliber it is.
The photo is self explanatory, but here are some instruction in case you don't read my writing good:
1. Air enters the center tube
2. Air pushes the large piston back, compressing both springs
3. Maximum pressure in, the little spring doesn't maintain the little piston in position, and pushes it backwards very quick
4. main spring returns the whloe system back in position one, and cycle goes on as long as air comes. what do you think????




Edit: The main spring could be replaced by a simple pneumatic ram.
Edit 2 : The air injection tube moves in and out the main cylinder.

i want to see it but i am busines class and the pictures are blocked

yeah, i think it will work., this first design needs improvements; the main neoprene disc must bu thick enough or simply hardened by two washers.

Theoricaly, it has the power of a single shot piston gun, but full auto. must be loud...i'm making a protoype as soon as i get my arc welder.

hey, i've done some little shots, with a very ghetto (i'll call this system the FAM-B) FAM-B, and the only springs i had allow me to inject 1.5 bars of air, and the velocity of the 0.20g airsoft BB's is 300 fps. imagine i put a pneumatic rod that allow actuation at 15 bars.......mmmh....velocity and control over the number of BB's you throw.
Unlike on a cloud or strafer, it is all mechanic and allows one BB per triggering.

I think I've finally worked it through.

Okay, the big sliding disk gets pushed back by air pressure but it's attached to the small barrel sealing piston by another spring and when the pressure builds up enough on the sliding disk it cracks open the barrel seal which flies back because of the tension of the spring - dumping air into the barrel.

Chamber is depressurised and springs reset everything.

Yes? Or did I get it wrong?

If thats how it works then yes I think it would work but you'd need some very strong springs, probably quite precise ones.... which could be an issue.

yes it's exatcly the functionning of the thing! for the main spring, i need to think about it, as i think it could be replaced by a pneumatic rod.

i can see it now stupid school, anyways, that is a cool idea, i think it should work. Are you going to make a good gun out of this. if so,cant wait to see it.

i'm going to do so, in fact, i'm going to make it the most complete and my last gun. i plan on using copper, steel; an arc welder; brazing; custom springs and pneumatic rod. automaticly fed springloaded magazine(or redirect a stream of compressed air at every shot...don't know for the moment.

0.88g steel bb's, 200 psi running pressure; semi/auto firing ; scope ; fully customized body ; carried pressure reservoir.
A small reservoir filled at each shot before dumping, for the semi auto option. check valve;
This sytem has the advantage over all other full auto mechanism, as it uses less air per ammo.

Wow sounds very good and if it does turn out to be better then all other BB guns you could be changing the design of BB guns for ever! Pitty its your last gun.

well, all the BB machineguns i've seen around request a damn big air supply to last a long time. I plan on using only a 6L fire extinguisher pumped at 240 psi. and this shoud last for ...........500-600 shots, but that woud say reduce the running pressure to keep the advantage of the high reservoir pressure, it need improvements, but i'm confident....

I am not sure it will be my last cuz i like to research and build'em. But i think i will have to put 'em on the side for a moment as my studies are getting harder.

how big will this be like the gun length wise

you should have two fire extinguishers in a back pack:)

i guess i'll use a 50 cm barrel, 6.02 mm ID, valve and per-shot resevoir should be 15 cm long....plus hosing, stock etc....

i think its a great idea and it will defently change the face of the bbmg
i am looking forwards to seeing this gun finished especially the custom body

Im a bit confused. Where do the bbs load from? is there a hopper you were using? Edit: nvm I just saw the part of the post about the mag loading.

But some advice anyway: If it is still in a prototype stage, dont go crazy with the welding. You'll probably need to tear things apart a lot until you get it all figured out.

_Fnord: I'm experienced enough to know what to do when entering in the beautiful but long time of building a spudgun! it's been 4 years since i started. Several clouds BBMG , a lot of pneumatics...(not posted here...) 2 combustions, a mini hybrid, a pulse jet mini engine.....So, i think i'm done with al the little things i've done.

For the magasine, yes it will be a hopper, it will be on the side, to allow me to use a scope on the rifle. I'm planing on building a more...common type of machinegun, not the minigun type that shoots 3000 BB's a second lol, only a repeater, that will allow me to shoot at long ranges, and multiple shots. I'll not refer to this design as a BBMG, but a multi-shot piston rifle.
I did some calculation....I don't think i'm gonna need less air, in fct if i want to have a lot of power, i'll need a large air supply at high pressure....