Gas Blowback system

[Corkie121]

Right then, I've been thinking of different ways to make a gas blowback system that could be dropped into existing airsoft guns without much hassle and would be run off of regulated CO2 to make it more consistant and cold weather resistant.

 

I've come up with a fair few that could be made, but all of them would involve alot of work to actually make and wouldn't be as realiable or accurate as an aeg due to the slightly inaccurate nature of the systems I thought up, (think paintball type changes in velocity per shot).

 

I did however have one thought which may work better, but by all means tell me it won't if you spot an issue with it.

 

The basic idea would be to buy a gas blowback pistol and take its main blowback component from the slide. The valve would be taken from the mag and the mag seal also nabbed.

 

Using a mill or similar, a frame could be constructed around the blowback unit to hold it in place and another for the valve. These two parts would be sealed together using the mag seal and a gas feed would be tapped into the base of the valve unit.

 

A trigger unit, set for either semi or fully automatic, (easier and cheaper to go for one at a time whilst testing), would hold back a hammer and once fired, the pistols components in their new housing would function as normal, however whilst being attached to the relevant charging handle of which ever weapon it is based in.

 

If mated with the aegs hopup, (or the pistols if easier), this could create a system that could be almost dropped into standard airsoft gun frames and turn them into gas blowback weapons for greater realism whilst still being able to use standard aeg mags.

 

Any thoughts?

 

Corkie

 

[renegadecow]

Having to stick to AEG mags will ultimately mean that the magazine will be in the way as using handgun GBB components will require both the power source and bbs be directly underneath the loading nozzle.

 

There are custom built as well as Madbull's CO2 gearboxes. Better off if you start from those. If you wanted blow back, all you really need is bleed off some of the escaping gas into a tube above the gearbox and pneumatically propel the fake bolt much like how G&G does it. If you wanted recoil, you'd have to somehow fit a floating valve at the exhaust to redirect gas to a heavy piston which would be your recoiling device installed wherever space is available.

[3vi1-D4n]

The other way is to:

 

1) Buy a real steel platform that takes AR15 mags (bushmaster M17 carbine, SA80, Steyr AUG that was modded to take AR15 mags)

2) Take the mag, hopup and blowback system from the AGM M4, transplant it into the said platform

3) Either lighten the bolt or custom make a new bolt

4) Find a suitable and lighter recoil spring

5) Get the hammer system off the AGM or a GBBP and adapt it to the trigger group of the said platform.

6) Great success!

[Stealthbomber]

Ok, here's a couple of thoughts.

 

First decide what you're going to do about mags.

 

The mags designed for the current breed of WA M4 guns won't go into an AEG cos the hop-up is all wrong.

 

So, do you build your gun with an internal power source that needs replacing every hundred shots or do you also invent a new mag that holds the gas and pumps it into the gun?

Alternatively, maybe you can find a way to modify AEG shell and engineer a new hop-up that'll allow a WA (or WE) mag to fit into your gun.

 

Once you've decided what you're doing about mags you can move onto the design of the gun itself.

Basically, I'd suggest you build something that fits into whatever gearbox used to go in that specific gun.

Sounds hard?

Probably is. I don't have all the answers.

I think this is a lock though. Whatever system youinvent needs to be a drop-in replacement for the gearbox.

This actually makes things easier in a way. You don't need to think about MP5s or M4s or G3s or G36s or AK47s. Just get yourself a V2 gearbox shell and a V3 gearbox shell and invent a GBB system that'll fit into it.

Once you've done that you're golden.

 

Bear in mind that if you've chosen to use some kind of gas-in-mag system you might need to modify the gearbox design so there's some kind of hammer at the front of the gearbox to actuate the mag valve.

Alternatively, maybe this is a good reason to go with a seperate gas supply and use AEG mags. That way your V2 and V3 gas gearbox can go in any suitable AEG regardless of it there are already gas mags available for it.

 

Next we need to look at realism.

People buy gas guns because of improved realism.

They're more realistic in the way they operate and more realistic in the way they can be field-stripped.

Pretty-much any gas gearbox system can forget internal realism.

That leaves realistic operation.

If you're using AEG mags you're going to struggle to build a gun that stops firing when the mag is empty.

So, you need to either figure out a way to make the gun stop firing when there's no BB in the chamber or accept that realism takes another hit.

 

And, with the AGM M4 currently selling for $120, you need to develop this new system and market it damned cheaply.

 

Seriously, if I was forced to do this (at gunpoint) I definitely think I'd be starting with a V2 gearbox shell and working from there.

I'd hope to create a simple gas gearbox that fires in semi and auto and could be fitted into any AEG that runs a V2 gearbox and sell it for about $60-odd.

[snorkelman]

Only practical way of starting to approach it without just rehashing existing designs would be some sort of extended nozzle on the bolt, allowing you to chamber into an AEG hop from an AEG mag.

 

firing from sear tripped open bolt system would simplify things a bit too if you're trying to shoehorn it into an AEG mechbox as bolt flying forward can be used to activate the valve knocker directly (removing need for a seperate hammer).

 

valve block Id try to shoehorn into space where trigger switch assembly normally goes lets it sit underneath your blowback bolt (then you'ld need to route external air to it).

 

I looked at using gas valve from commercial mags as a shortcut for a gas blowback sten (albeit with an RA-tech NNPAS bolt from a GHK AK held insiid a sten like bolt that would act as blowback chamber, rather than bolt and chamber from a pistol), though plan there was to still have the mags gas fed - it certainly saves a little of the more precision work but you've still got rest of the engineering to take care of however you slice it

 

 

[BigEd]

There was a system available a couple years ago. It was a drop in replacement which replaced the cylinder set, while the rest of the system remained the same. Was adjustable up to 500-600 fps. Based on the principle of a hammer valve system.

 

The selling point was, if it had a cylinder set, it could be put in.

 

(V3 box pin pic)

 

Do not know what ever became of the system.. (Not produced by MadBull)

 

///ed///

[Corkie121]

Cheers for the feedback.

 

Based on what you've all brought up, I think that using a gearbox shell as an outline so that it can drop straight in and an extended nozzle on the blowback unit to feed through aeg mags, hop-up and chambers.

 

This would fix the feeding issues as the gas would be externally fed from behind the loading nozzle and the bb's would be loaded from the standard mag well.

 

This seem better?

 

Corkie

[X Lupin]

Research the escort system. It's pretty easily copied, and does everything you want.

[Corkie121]

Research the escort system. It's pretty easily copied, and does everything you want.

 

About that.. I saw a diagram and frankly it looked pretty complicated. Could have just been the schematic I looked at but I'm not sure.

 

Corkie

[X Lupin]

About that.. I saw a diagram and frankly it looked pretty complicated. Could have just been the schematic I looked at but I'm not sure.

 

Corkie

 

Have a look at this moving diagram, it's actually quite simple...

 

[Yuri]

Thanks for that Lupin, very interesting. It's funky how it recoils first and then fires.

[Horsem4n]

theres a small problem with the escort system though. the rate at which the bolt returns to battery sometimes pushes the BB passed the chamber and right up to the hopup, causing accuracy inconsistencies. now, i like this system, but its not perfect. i think, for the better of accuracy, the BB should leave the gun before the other parts start to move. however, ill have to trust the weight of the moving parts not to hit the BB passed the chamber

 

i understand what the OPs design is. thinking of it, it is possible. the BBs do not need to be under the loading nozzle. a separate ram linked to the nozzle, behind the AEG hop up will load the BBs. ill draw a diagram and get back to you guys.

[Horsem4n]

it will take me a while to do this. the whole thing seems to frikken huge to fit in a gun.

[X Lupin]

it will take me a while to do this. the whole thing seems to frikken huge to fit in a gun.

 

Too big.... For the PAPOP?

 

 

I think not.

[Corkie121]

Never seen that diagram before, cheers for posting it.

 

The P90 would solve the mag feed issue by just dropping the bb's into the chamber in front of the nozzle, however im interested in seeing how Horsem4ans'design looks.

 

Corkie

[Horsem4n]

my design is mostly complete, but id rather work on it more before posting so it at least looks modular and fits in an armalite.

 

it involves parts from a detonics and desert eagle other than fabricated parts.

 

the part i havent figured out is the hammer assembly. i may take it from a glock for space reasons. every other pistol uses a linear spring to drive the hammer, located in the grip. the glock uses a circular spring in the hammer and no mechanics in the grip.

 

i used the piston/cylinder asembly from a DE because its self contained and LARGE. its got 2 wings coming off the front to mount a recoil spring too if needed.

 

i used the recoil spring assembly and hop up unit from the detonics because the recoil spring/guide/bushing are all self contained, small and strong. i used the hop unit cause its small. the problemim going to have to overcome is having the DE's nozzle seal against the detonics hop for gas reasons.

 

 

this whole thing is about making a GBBR out of GBBP parts and uses AEG mags right?

[Corkie121]

my design is mostly complete, but id rather work on it more before posting so it at least looks modular and fits in an armalite.

 

it involves parts from a detonics and desert eagle other than fabricated parts.

 

the part i havent figured out is the hammer assembly. i may take it from a glock for space reasons. every other pistol uses a linear spring to drive the hammer, located in the grip. the glock uses a circular spring in the hammer and no mechanics in the grip.

 

i used the piston/cylinder asembly from a DE because its self contained and LARGE. its got 2 wings coming off the front to mount a recoil spring too if needed.

 

i used the recoil spring assembly and hop up unit from the detonics because the recoil spring/guide/bushing are all self contained, small and strong. i used the hop unit cause its small. the problemim going to have to overcome is having the DE's nozzle seal against the detonics hop for gas reasons.

 

 

this whole thing is about making a GBBR out of GBBP parts and uses AEG mags right?

 

It is indeed, I chose the Detonics for its low cost and size. The Scorpion may also be a good donor gun.

The trigger mech in full auto is very small, one sear and a trigger. The hammer mech could either be stolen from a gun or made using a pin and linear sping with a small lug to engage the sear.

 

Corkie