complete opposite of FSDO on classic mag

[SOAD8789]

well, it seems the first shot over the chrono is always a bit high....a bit too high, like 320 or something. it goes back down again though after the first shot, but if i leave my mag sitting for more than 10 min, it'll do the same thing. its fine for the most part...but it irks me....any solutions for this problem?

[Matt Crawford]

Clean/lube the valve/reg(on valve) Also that big fat oring between the valve halves(sorry forgot name) may need replacing or oiled.

[personman]

Matt: Fat oring = reg seat :)
Yeah, check the reg seat, but also,
Are you using co2?
You know that heat causes co2 to expand, so if you leave your gun sitting, then the chamber pressure will build and may cause that problem.. thats just a little theory I just thought of though.

[speeddemon]

Matt: Fat oring = reg seat :)
Yeah, check the reg seat, but also,
Are you using co2?
You know that heat causes co2 to expand, so if you leave your gun sitting, then the chamber pressure will build and may cause that problem.. thats just a little theory I just thought of though.
Not just CO2, same thing with any gas. Leave any gun sitting in the sun, and the first shot will be hot, maybe not by much, but at least some.
Sounds like a reg seat problem, just get a new one.

[the electrician]

it's just the reg seat. I'd get a rebuild kit. it has a reg seat in it. slap a new one in.