Stop a gas gun blow back function during semi single shot

[N_Force]

These day I'm bored and would like to ask and do something stupid, anyone could give me ideas or even answers before I try it.

If I blocked a WE M4 bolt to stop it blowing back, set it to semi auto and fired single shot, what do you think it would happen? Has anyone tired it? Or something like this?

[pestobanana]

All of your gas would spray out and freeze your gun.

[e-luder]

^what he said...


Your bolt actions the hammer and the hammer (uncharged) prevents your firing pin from actioning; thus will keep your blowoff valve open until gas runs out (or until you charge the gun via charging handle or drop the mag).

Lamen's terms: The firing pin will not charge (then blowoff valve pushes back on the firing pin) until it is "allowed" room to do so. It can't charge if the hammer is isn't charged...

im confused by what i just said.

You can see this happening yourself. It's happeninng when your mag runs low on gas and can't action the bolt fully anymore. The system just vents gas until there is no more or until you manually charge it or until you drop the mag. So, you can try it yourself. try it on a pistol or somthing. It's the same principle and same result...

[Wilkie]

That sounds like something akin to dividing by zero to me.

[pestobanana]

What ESL-luder meant was

The hammer hits the valve knocker which opens the valve. The knocker does not allow the valve to close until the slide or bolt moves back to cock the hammer. Until then, the valve remains open.

[e-luder]

^ ye....yeah...THAT's it

What's the answer to a divide by zero?

[MultipleParadox]

42?

[e-luder]

...(I knew that)....

[sundae_1021]

it's not gonna shoot at all or load a round in the chamber because you block the bolt from moving back.

[N_Force]

Thank you for those experience expert answers, so if blocking the bolt, the trigger would not be having blow back to release the firing pin from release valve and dump all the gas at once, that's how the wat gbb design for - need blow back to reset, since I've got a bit attention, I have next question. I tuned up my gbb as of my hobby, but hardly ever get into the design theory. I would like to know how's the design for a "non blow back" (pistol mostly, oay be rifle)working? Comparing to semi and auto gbb?

[Drake]

An NBB works in a similar fashion except the knocker pushed the gas valve open (inertia) and gas pressure and a return spring on the valve allow it to close again.

The main difference with a GBB is that in a GBB the knocker is being held in place until the action cycles.

In both cases the gas will vent when pressure drops too much (empty mag, cold weather) but for the GBB its because the action can't cycle and for an NBB its because there isn't enough pressure for the valve to close itself.

[N_Force]

Thanks Drake. So the nbb function is based on a return spring and gas pressure (push back) to cut off and stop the gas flow, like revolver or SAA hammer design, right?

[Danke]

The NBB is like a DA revolver. Thus a heavy shitty trigger pull.

[Ricochet]

What's your end game, silence?

[Bellerophon]

Originally Posted by N_Force

If I blocked a WE M4 bolt to stop it blowing back, set it to semi auto and fired single shot, what do you think it would happen?

The best you could do is buy or make a buffer that will short stroke the travel of the bolt, as in this video (the buffer is in this case the brass part visible 35 seconds in).