Blowback system, will this work?

[bookyle]

Hey guys

I thought of an idea on a blowback system to be used on airsoft/bb guns.

The brown part is what gives the blowback feel.

The brown bolt could be made of some heavy material, like brass. It moves back, letting air push the blow forward purple valve, which in turn loads a bb and fires it. The middle gray part does not move.

The black dots are supposed to represent O-rings.

The hardest part to get this system to work is probably getting the spring tension right since there are two valves and they need to work in sync.

The pressure supplied should be in bursts, like a QEV+popoff or a 3/2 valve with a chamber.

What do you guys think?

[jackssmirkingrevenge]

So basically the grey part is fixed, the brown part blows back first then allowing the air to go through the purple part which blows forward?

The concept is sound, but do you have the resources to make it?

Epoxy is a way to do it:

[youtube][/youtube]

... but it's not so straightforward.

Or you can commission some machined parts

[Gun Freak]

Seems a little more complicated than it has to be to me. I think JSR's blow forward design is about as simple as it gets. However I do like the way you incorporated two valves into the whole little system. But again a little too complicated. The biggest problem I see with it is that the flow through the system is a little interrupted because it has to go around too many parts. Will it work? Sure, if you make it right and tune it in perfectly. Is there a better and easier way? Probably.

Just my 2 cents!

[bookyle]

The point of this system is to get the blow back feel of a firearm. If I was just going to send some bbs down a barrel, then yea, the blow forward will be a easier design.

Other than this, I can't think of a simpler blowback design.

[Gun Freak]

I can, I'll post a little diagram.

This is extremely simplified for ease of drawing in MS Paint, but you should get the idea. This design could not be used with a constant air source because it would probably just stick open and not re-cycle. QEV pop off or semi auto via three-way valve would be optimum in my opinion.

[bookyle]

Wait, but with this, the gas is going to leak through the magazine.

[Gun Freak]

The mag can be capped off and made airtight I suppose...

[jackssmirkingrevenge]

I can, I'll post a little diagram.

Hmmmm....

[Gun Freak]

Well fancy that Jack!

[FelipeL]

I hope there aren't any air taxes in your area!!!!

[Zeus]

If you want a pretty simple system, look into gas blowback airsoft guns, they work very well, decent reliability, and effective. Also capable of some solid recoil if you want

[wyz2285]

If you want a pretty simple system, look into gas blowback airsoft guns, they work very well, decent reliability, and effective. Also capable of some solid recoil if you want

That's why i got a GBB SCAR! I'm gonna open it up to finally see how do they do it rather I've underestimated the power of low pressure acting on a large area or these propane are magical
I was building a similar system as Gun Freak and JSR posted, right now I'm just not decided to use a QEV+3-way (I will make them myself of course as I need custom sizes) or a hammer valve. Hammer valves are more consistent and higher air efficiency and easier to suppress but QEV+3-way are more simple. Do you guys think that duo to the aerodynamics of the bb, the inconsistency of a QEV+3-way is insignificant?

[Gun Freak]

If you're making something as precise as that I would think you'd want a very consistent valve as well, so a hammer valve would be my choice. But you may as well test the blowback with a QEV before machining the whole hammer valve system...

[Zeus]

Wyz, inconsistency will throw your accuracy to shïte, so hammer valve all the way.

GBB SCAR, WE I hope? If you'd wanted to know the majiks I could have shown you the internals of a WA Magna system. It's so simple it hurts, just remember you need to do the maths for it. It's really easy.

I'm getting myself a G&P Challenge kit, if you want to know the instead and outs of a GBBR that's the way to go.

Edit: I never mentioned, PUI FTW!!!! Time to smack on the cowboy hat and be the Marlboro Man hahaha

[wyz2285]

Yap the WE SCAR GBB open bolt.
I really should have gotten a Sun project as it would be a thousand times easier for me to mod.
If you could e-mail me all the photos/diagrams that would be great mate