exhausted-can't think straight

[vintage]

I have a micromag branded Retro valve that I installed in a micro and on 850 psi it is reacting so bad its unshootable, it will chuff if I short stroke the trigger or go pffffft. I install a new on\off pin I bought from AGD(the longest they list now is .745) and it made no difference. I put the valve in a different micro and it still did the same thing so its the valve and not the body. I know its got to be something simple but i'm working 84 hours a week and am not at my best for tech work.

thanks in advance.

[athomas]

By "reacting", do you mean reactive? Or do you mean it is "unshootable" because it is not shooting properly?

What bolt is installed, a level 7, or a level 10? How old is the bolt spring? A worn bolt spring will cause chuffing, especially on a level 7 bolt. Have you completely cleaned the valve and checked the orings? That is always the next check after the bolt spring.

[MAGgot]

Yeah, which bolt? If lvl 7, a shorter PT spacer should fix that.

[athomas]

Yeah, which bolt? If lvl 7, a shorter PT spacer should fix that.

No. Actually a longer one will help. A shorter one will contribute to short stroking.

[athomas]

I have a micromag branded Retro valve that I installed in a micro ...... I put the valve in a different micro and it still did the same thing...

I just clued in that it is actually installed in a micromag body and not a micromag valve installed in a standard mag body.

A micromag body requires the use of a much shorter on-off pin. You should probably use a 0.685" pin in this valve if you are installing it in a micromag body.

[MAGgot]

No. Actually a longer one will help. A shorter one will contribute to short stroking.

From his description chuffing is the issue, not short stroking. A shorter PT spacer will eliminate the chuffing.

[Tunaman]

Athomas is right. The .745 pin will not work. God only knows what size will work though. Grind it .005 off until it shoots.

[MAGgot]

Shoot me a PM as a reminder and I'll measure some Micromag RT pins tonight.

[athomas]

From his description chuffing is the issue, not short stroking.

Chuffing is the sound of a short stroke. He said, "it will chuff if I short stroke the trigger...". A shorter powertube spacer stops air leaks when the bolt is sitting in its stationary reset position by allowing the oring to sit tight against the back of the bolt stem. If the spacer is too short, it prevents the proper bolt reset or slows it down, which causes short stroking if the next trigger pull is executed too soon before the valve can recharge in the reduced window of time. If that happens, you will get a cough or "chuff" sound.

[vintage]

told you I wasn't thinking straight, forgot to say its a level 7 bolt and I just realized I need to pull the on/off assy out of the other one and see if it changes anything.

[MAGgot]

Chuffing is the sound of a short stroke. He said, "it will chuff if I short stroke the trigger...". A shorter powertube spacer stops air leaks when the bolt is sitting in its stationary reset position by allowing the oring to sit tight against the back of the bolt stem. If the spacer is too short, it prevents the proper bolt reset or slows it down, which causes short stroking if the next trigger pull is executed too soon before the valve can recharge in the reduced window of time. If that happens, you will get a cough or "chuff" sound.

In my experience maintaining a rental fleet of mags, there are some that do not quite leak down the barrel after installing a fresh o-ring, but chuff on each shot. A shorter PT spacer solves this problem.