Research: Different Gas Systems

[Cosmitz]

I'm doing a bit of pre-project research, and i'm interested to know how do different gas shotguns operate. While i have handled a bit of gas handguns, gas shotguns are rare enough that i could not dissect one until now, and the concept of multiple bb's is puzzling to me.

 

-Gas/bbs in the shell. What are the limitations, shells/gas wise, examples of shells, modus operandi. I'm imagining sorta like grenade launcher shells, just smaller. Correct?

-Gas somewhere else, bb's in the shell. Do the bb's load separatly in a chamber and then the gas affects that chamber, or does the gas 'flow through' the magazine? I would work with this as bb's stored in 'discs', which have the rear exposed, where gas can push them through the mag.

-No shells, gas somewhere, bb's come from a 'boxmag'. This would be the hardest to do i'd imagine, but the best for what i might do. How to regulate gas going out. How to 'load' bbs into whatever firing chamber and making them sit there and not just roll out of the barrel.

 

I'd appreciate any info/diagrams/schematics you have on hand. Thanks.

 

LE: I did not mention airsoft flamethrowers because of the waste in gas, and the fact that they are designed to give a 'stream' of bb's, instead of 'shots'.

[Falcon_ASVV]

I'm doing a bit of pre-project research, and i'm interested to know how do different gas shotguns operate. While i have handled a bit of gas handguns, gas shotguns are rare enough that i could not dissect one until now, and the concept of multiple bb's is puzzling to me.

 

-Gas/bbs in the shell. What are the limitations, shells/gas wise, examples of shells, modus operandi. I'm imagining sorta like grenade launcher shells, just smaller. Correct?

-Gas somewhere else, bb's in the shell. Do the bb's load separatly in a chamber and then the gas affects that chamber, or does the gas 'flow through' the magazine? I would work with this as bb's stored in 'discs', which have the rear exposed, where gas can push them through the mag.

-No shells, gas somewhere, bb's come from a 'boxmag'. This would be the hardest to do i'd imagine, but the best for what i might do. How to regulate gas going out. How to 'load' bbs into whatever firing chamber and making them sit there and not just roll out of the barrel.

 

I'd appreciate any info/diagrams/schematics you have on hand. Thanks.

 

LE: I did not mention airsoft flamethrowers because of the waste in gas, and the fact that they are designed to give a 'stream' of bb's, instead of 'shots'.

 

1. Yes you're right, it's about the same as 40mm Grenades.

2. The Maruzen pushes the gas through the shell while the BBs are still inside the shell.

3. This one is actually the easiest one if used with just 1BB per shot like in most of these guns.

You just need to move a Nozzle when cocking the gun and lock the trigger to not open the valve while not in full forward Position.

You could also move some kind of gear while cocking which operates a tappet plate, so you can make one cocking procedure execute mulitple feeds. into a custom hop up chamber.

 

[Cosmitz]

Thanks for the reply.

 

3) For my project i'll need to shoot atleast some 8-10 bb's, i'm talking spread> I'm imagining a bunch of BB's just fall into a chamber, where they are held there by 'magic' or something, and a burst of gas pushes them out.

2) This is very interesting. Since i can make a reloading system in the form of discs or something and have them cycle. Care to give more details on how this works, and examples of Maruzen shotguns that use this design?

1) This will make it extremely easy to make my project, if nothing else works, since all i'll need is a pin to push the 'button' in the butt of the shell i assume?

 

[Zmarre]

3) is exactly how the ACM M500 gas shotties work, and is quite simple. Even with 10 bbs, you just have to make the chamber long enough to fit the 10 bbs in a row.

[Cosmitz]

And don't they 'fall out'? And how is the system being fed? To prevent overloading/underloading?

[shmook]

i will take some pics this weekend for you, of an acm gas shotty, which i am fettling for a friend. i need to pull it to bits anyway, so no problem.

 

and also of some maruzen shells, if that helps

[Cosmitz]

Thanks, that'll help immensely. I'm marking up a project auto-shotgun, so you can see why i'm so interested in finding out the best way to work with gas/bbs. How many bbs are stored in those shells and how are they 'fired'?

[shmook]

with maruzen, the shells can hold any number between 1 and 10 bb's

 

they are basically a tube, long enough for 10 bb's, with a rubber lip at each end to hold ammo in, similar to the end of an AEG hop rubber which mates with the air nozzle.

 

this is encased inside a plastic/brass shotgun shell shaped outer casing.

 

the shell is pushed up against the barrel when loaded, and the rear is mated with a nozzle, through which the gas passes, forcing bb's out of the shell, and down the barrel.

 

hope that makes sense!

 

as i said, pics this weekend, but they are stupidly simple. the loading mech on the gas pump action is nice and simple too, but no idea how to convert to auto...

 

anyway, pictures speak a thousand words

[shmook]

apologies for lack of pics as promised, but should hopefully get them up on wednesday

[Cosmitz]

Not a problem. This is a long-term project anyway. No hurry.