pneumag operation

[ProblemKinder]

hey, i've seen threads and pictures explaining how to build a pneumag, but could someone give a brief (or extensive, your choice) explanation as to how they actually work, using parts names like QEV and MPA and what-not. i would just like to have as good an understanding as i can get before i build one. thanks in advance to anyone who chooses to enlighten me

[sTaLa]

Instead of pulling the trigger and pushing the sear with your muscles, you activate a valve. The valve (MSV-2 for example) will let air passes and will active a piston (MPA3). The piston will push on the sear.

A QEV is to have an even faster ROF. It kind of depressurises the tube between the MSV-2 and the MPA3 I think. But it is not a must to have one in any way.

A low pressure regulator (LPR) must be installed to route air to the valve (MSV-2)

I hope that helps.

[ProblemKinder]

that's awesome. just out of curiosity, what does the LPR lower the pressure to?

[Temo Vryce]

The LPR drops the pressure to less than 100 PSI. Believe that most run it between 50 - 75 PSI, but I could be wrong.

[ProblemKinder]

awesome guys, I appreciate it.

so, who could drill and tap my fore grip to accept a front mounted LPR? how does air get from the LPR to the internals? is it through one of those tiny hoses that connect the piston and the 3-way?

[t0nnn]

yeah, but you don't have to tap your asa to mount the lpr, if you have a bottom asa with an extra port you can put the lpr with a 90* fitting right on there. Depends what you want tho

[Ydna]

Pneumag animation http://www.zdspb.com/media/tech/anim...eumag_5fps.gif !!!

[ProblemKinder]

that's actually pretty helpful. can you tell me where the QEV goes in that picture?

[Ydna]

A QEV would replace the air fitting attached to the actuator. The only thing that's largley inaccurate about the animation is that the actuator's air fitting usually has to be attached to the bottom side of the actuator, not the end of it like shown. From what I gather, there typically isn't enough room with the trigger installed, so it has to go into the side instead.