Minimag problem

[leloup]

So I am building a mag for my father's birthday coming up next month, and I have almost everything working well...except the valve. When I gas it up (carrier size .225) there are no leaks. When I fire, it sometimes fires fine for two or three shots, then sputters, shoots air out the bolt constantly, the bolt might even stick forward a little at times. Is this bolt stick? I changed to a larger carrier, I don't have a .230, but I do have a .235, and that was like a fire extinguisher. Is it the carrier size that is the problem or is there something else that is causing this? The valve, again, is a minimag w/ lvl7.

[athomas]

Sounds like bolt stick issues. Have you replaced the bolt spring lately. They are a consumable item that needs replacing from time to time. A weak one can cause bolt stick issues.

You should install the powertube spacers so that you are using one shorter than the one that leaks when the gun is resting and ready to fire. (ie; if the gun does not leak when at rest, then the powertube spacer is not too long). Go with the longest spacer that does not leak. That will ensure that you are not getting spacer induced bolt stick.

[leloup]

So it is possibly the spring, and not the spacer? Now I am going to have to find some new springs...

Would that cause it to not fire some times and just vent?

[fhawkeye]

I don't think it's suppose to leak when the bolt sticks, remember if the bolt doesn't return all the way the on/off should still be keeping air back.

Not firing and just venting: turn your regulator screw in.

[athomas]

It isn't supposed to leak, but it will for a while until the residual pressure in the chamber is released to a pressure low enough to allow the bolt to fully reset. Its the sputtering and sticking that makes me think it is the bolt spring. There could be a problem with the on-off top oring as well if the air doesn't stop on it own after a while following a stick.

[leloup]

I'll try switching out both and see what happens. Thanks guys.