Actuator on Pneumag question

[EvilCreature]

I was wondering how the actuator (MPA-3?) on the pneumag prevents double firing. Is that the operation of the mag that prevents a double fire, is it the design of the actuator itself, or is it in the 3way? I see people hold down the trigger for a long time... if the actuator stays forward, wouldn't that keep the sear open, causing the gun to cycle numerous times? Or, at the very least, cause the actuator to cycle numerous times upon recharge, thus the gun fires numerous times.
I am asking because I want to use an actuator in a different application and want to know if how it prevents double firing before I invest too much money into the project.

[BigEvil]

Your over thinking.. If the actuator keeps the sear all the way back, it is the same as holding the trigger on a regular mag. The gun would fire once, and then stop.

You are thinking RT bounce. Unless the actuator is just barely touching the sear, you shouldnt have that problem.

The actuator moves once per trigger pull.

[EvilCreature]

Ok, so it is the valve on the mag shutting it off... I am trying to apply an actuator to a regular seared gun. Holding the sear down on a regular gun would cause multiple shots, correct?

[BigEvil]

Ok, so it is the valve on the mag shutting it off... I am trying to apply an actuator to a regular seared gun. Holding the sear down on a regular gun would cause multiple shots, correct?

Nope

The actuator is controlled by the MSV thingy.. which is bascially a 2 way valve. The actuator 'moves, works, fires, whatever you want to call it' when you push the little lever on the MSV2. ! pull = 1 shot.

The same principle should be applicable to any sear tripper. The mpa3 just takes the place of your finger, which is normally attached to the trigger, which normally hits the trigger rod, which moves the sear.

Search Pnuemaggers threads,... there are tons of pictures and better explanations

[FinchMan]

If you want to put a pneumatic trigger on a blow-back sear tripper, then you'll need to figure out a way to let the sear catch the bolt after it cycles. The actuator will need to be coupled with the sear with a mechanism that requires the actuator to reset before it can trip the sear again. If you look at the mech trigger on your blow-back gun you can see how they did it. Maybe that will help you design the mechanism you'll need.

[Lomarandil]

Yep, I ran into this problem when I was trying to build the pnuespyder.. ended up as the pnueblender for that reason...

I'm not finished tinkering, but the budget isn't allowing much work on it for a bit.. (dremel died), so we'll see how this goes...

Lo

[benzy2]

On a mag when you pull the trigger the valve shuts to the closed position before the bolt is released. No matter now how long you hold the trigger the valve is still off and no more air enters/shots fired. This is why it works great here. All you really do is remove the trigger rod and use the mpa3 to move this sear. As said in a blowback the sear has to catch and doesnt stay down after each shot. There is a lot more work to get a blowback sear to work. What does have potential would be an autococker. There you can remove all interface with the sear and the trigger and replace it with the same setup used in pneumags. The only problem is that you still have to time the gun and you still have to have enough spring tension to reset the cocker 3way which is much higher than the msv2 and as such the pull isnt near as nice.