Pneumag on/off

[bjyourk]

Just got a pneumag frame (thanks mag79) and was wondering which on/off to use....stock or ULT. With just some preliminary tinkering the stock on/off just makes the gun go auto and for the ULT, it just would not fire (tried a few shim combos). Suggestions and should you stick with the same spring?

Thanks

[mag79]

Just to let you know the frame is fully tuned, no need to mess around with the LPR. Notice on the bottom of the frame, when you install the reil for your on/off, the back screw needs to be real short. If not you will damage the brass 90 fitting. Also if you remove the grip panel, the 2 shorter screw belong in the top.

[bjyourk]

got it. What about the on/off(stock or ULT)?

[snoopay700]

Stock will work, ULT will allow for a lighter trigger pull because you can use a lower psi, but it's not needed and i doubt it will make much of a difference.

[bjyourk]

well thats whats in now but it shoots full auto for about 6-8 cycles. Is that a spring issue or something else?

[Spider-TW]

What kind of valve, frame, and rail do you have?

Check that the sear is allowed to go all the way forward (latches up on the bolt) without hitting the ram in the actuator (MPA-3?). If it keeps the sear from latching up, you can file or grind a little off the ram or the sear leg.

Was the LPR set up on a ULT or a stock on/off?

[bjyourk]

Its an intelli frame. as far as the on/off original setup, I dont know. I had the ULT in my valve when I put it on my marker and it would not fire all the time(seemed like the sear would not have enough kick to push the pin). If I pulled the trigger and held it back, it would work fine.
I added/deleted some shims but still would not work properly. Thats when I switched to the stock on/off.

By the way: xvalve with LVLX

[snoopay700]

Try the stock on/off, my guess is it'll work with the pressure you're set up at and it'll probably be more consistent, and the trigger will be the exact same.

[Spider-TW]

I had the ULT in my valve when I put it on my marker and it would not fire all the time(seemed like the sear would not have enough kick to push the pin). If I pulled the trigger and held it back, it would work fine.
Actually, it's the other way around; the pin doesn't have enough force to push the sear.

The air pressure from the reg pushes the pin back out, forcing the sear up. When the bolt returns by the bolt spring, the sear is pushed up to catch it. Releasing the sear with your finger or with the MPA-3 pushes the pin up and shuts off the gas while the bolt releases the air built up in the valve body.

"Auto" fire is caused by problems between the on/off, the sear, and the bolt. If your old frame works on the valve and the pneu frame cycles fine, the problem is probably in the fit between the sear and the MPA-3. If nothing else, try loosening the frame screws and retightening them while pushing the frame towards the front of the rail. :)

[bjyourk]

So the point at which the piston/rod makes contact with the sear should be moved forward therefore allowing the sear to drop down into the rail more......Correct?

[Spider-TW]

Sort of. The hope is that the whole MPA-3 assembly (and frame) can move a hair forward, leaving more room for the sear arm to come forward and the sear can get a better grip on the bolt. *The actual bolt catch moves up*

This is all relative to the threads on pneumags and "the gap" between the MPA-3 and the sear. You can see the "final" position of the sear only when the pressure in the valve body is pushing the bolt out against the sear. Then, all of the slack is pulled out of the pin to rail fit (classic rail only) and the pin to sear fit and the angle is affected by the shape of the sear and the condition of the bolt lip. Pushing the sear down with your finger is not exactly the same.

Anyway, flip the grip open when you have it pressured up with a barrel sock on and see if you can find at least a tiny gap between the sear and the MPA-3.

Does your stock on/off work in a regular frame?

[mag79]

If you want, send it back and I'll see if its the frame, I am only a state away. It shot great before I shipped it. Did you modify your sear?

[Spider-TW]

I wouldn't be surprised if this is a common issue on a lot of e or p frames moving from one marker to another. The original arrangement is a screw adjustable trigger rod and the front of the sear leg doesn't have to meet a tolerance anyway. Not to say AGD didn't try, but why would they check it?

If the two pieces work separately, it's just a matter of getting them fitted up.

[bjyourk]

First off, thanks for the offer mag79 but as Spider said, I believe it to be a matter of tinkering.

Spider, do you mean to say that there SHOULD be a gap between the sear and mpa or NO gap? Right now there is no gap.

And about the stock on/off, it worked last time I had it on. I had been using the ULT though until I got the Pneu frame.

And whats this stuff about modifing the sear. I took the rod and fork off but is there more to do? (possibly the missing piece of the puzzle that is my ignorance).

[mag79]

No you did it right, all you had to do is remove the pin and fork. The mpa will not move, it is secured by 4 set screw, 2 that screw into it.

[captian pinky]

well if there isnt a piece in the mpa3 that sticks out to puch the sear then u have a little work todo

[Spider-TW]

Spider, do you mean to say that there SHOULD be a gap between the sear and mpa ?
Yes, there should be just the slightest gap. It guarantees that the MPA-3 piston is not keeping the sear from latching up completely. It could be as large as 1/16", but any gap you can see when the marker is pressured up should be fine.

You don't HAVE to modifiy the sear, but if you are auto firing, the sear hitting the MPA-3 at the end of the bolt return is a definite candidate for the problem. You don't want to mess with the MPA-3 mounting. You can sand a little metal off of the MPA-3 ram where it hits the sear, or sand a little metal off of the sear where the ram hits it.

It's easier to pull the sear out in your hands and sand it off in the right spot. It's easy to do, easy to clean up, and you should NOT be taking off enough to get into the clevis mounting hole, so you will not be ruining your sear. Like I mentioned before, where the MPA-3 hits the sear is not a normal working surface. It will actually be some tenths of a gram lighter, just like the new parts of latest and greatest markers! :rolleyes: You shouldn't need to take off more than about 1/32" (maybe a little more) if catches the bolt sometimes.

You can sand or grind the MPA-3 ram down, but it's harder to get to and you need to keep the metal particles out of it.