gass assist

[spelunker]

sorry if i sound stupid or if this is already covered somewhere else on the forum. my friend is working on a project, and he was trying to see if he could construct a gas assisted design for a gun. in principle a pressurized gas forces the bolt and firing pin foward and back, with maybe some spring assist somewhere in there. the gas source would be a co2 canister in this case. he was wondering if anyone has any knowledge with this or could direct him somewhere where he could get the blueprints of an already existing design, ora person that would have some knowledge on this topic. so far my friend has vary limited knowledge on this topic, but has constructed a thing that can fire 5 blans in sucession in a few sec. yes, quite a far step, but this is what this place is for, gain knowledge. there was supposedly one gun of german design that had a similar system, or at least that's what we understood. thatnks everybody in advance

[irish]

Most (all ?) gas operated guns use the propellant gas tapped at some point in the barrel.
If you used a gas canister you would find it would run out at a very bad time or run low on pressure and not unlock/lockup the action.
I'm sorry to be negative on your idea but I think you would find it better to work on a blowback or a normal gas action.

[FragmentedSanity]

Lo there.
Just a suggestion - but it might be a good idea if you edited your post to tell us more about this "thing" that rapid fires blanks. Pictures - details - drawings... something more than "thing" You might also look athttp://roguesci.org/theforum/showthread.php?s=&threadid=2774
I have to wonder why you want to make a gun like this tho - it seems ovrely complex.
If you want to use compressed CO2 why not design an air pistol - or if you just want a gun make a blowback Semi - or Luty's sub 9 or something..
later
FS

[Arthis]

If I understood well you want to make a gas operated system that would transform your semi. auto in a beautiful automatic pistol that would fire really fast, by acting on the bolt ?
This seems much work, even though I don't know much about that...

[ancalagon]

in principle a pressurized gas forces the bolt and firing pin foward and back

This is kind of the principle of most semi and automatic guns anyway. Basically, the pin hits the back of the cartridge, which triggers an explosion, which forms into pressurized gas, which pushes both the bullet forward and the pin back. You don't really need an external gas source for a hand held gun, although I could be misunderstanding you or your friend's goal.

-Ancalagon

[knowledgehungry]

The goal is to make a full auto gun from scratch.

[zaibatsu]

I can't see how that could be Blindreeper, surely any sensible person would not use an external power source and just either use blowback (as ancalagon stated) or bleed gas off from the barrel to a piston which then unlocks the main bolt. Therefore I believe he must be talking about an "add on" system for a regular rifle. However, it would only really work on a semi-automatic firearm, and then there are much simpler ways to do this (unless we are talking about airguns?). I think we need more information on the type of firearm, calibre etc before we can comment on this idea.

[knowledgehungry]

Firstly i am not blindreeper, secondly i know this fellow firsthand(it is neither I nor spelunker), he has already built a rifle from scratch. What he wants to do is make a gun similar to this from scratch. http://world.guns.ru/shotgun/sh18-e.htm

[zaibatsu]

Knowledgehungry:

Firstly, apologies for the mistake in name, god knows how that happened. But, that shotgun (or the CAWS project) seems rather ambitious, and what benefits does it have over other semi-automatic shotguns? Sure, it can fire high pressure shells, but why not just use brownings design? Or use the same principle as a normal gas-operated shotgun? Your friend should have known to include more information, or you should have told him to read the rules more carefully.

Why don't you get your friend to post more details of what he actually wants to achieve, so we can help more?

[knowledgehungry]

First of all i am very inexpierinced with firearms, not my current thing. Spelunkers and my friend does not have access to this forum, not due to being banned or anything like that. I will try to have him get me a write up as soon as possible, and i will post it then. Spelunker you should have read the rules, not only that, since this is your second post you should have had me post this or at least done a more thourough job describing the goal of our mutual friend. Try to make your posts look a little more professional next time eh?

[ancalagon]

You can make a fully automatic shotgun from scratch more easily with a blowback type design than with a seperate gas system. Also, looking at the blueprints at http://www.securityarms.com/20010315/galleryfiles/0700/782.htm I can't see where the design includes something like a CO2 cartridge.

-Ancalagon

[knowledgehungry]

Well I talked to my friend, and he thinks he has it all figured out, if he gets it to work ill post pictures and what he did exactly. So thanks for your time.