Classic valve going uncontrolled full auto

[Drachen]

I recently built up a new mag with an existing classic valve level 7 bolt I had sitting in a box for the last 10 years. I don't remember ever having it in a gun, so as far as I can tell it has not been used in a looong time.

I tried airing it up last night, everything holds air (after installing the on/off the wrong way...twice), but at first when I tried to shoot it, there was some weird bolt stick type of problem that if I pulled the trigger a second time the bolt would come back and fully cycle, but then go back the next pull and not return. I replaced the bolt spring with a longer (red) spring, and that solved the bolt stick, but now it sounds like it's going full auto and won't stop until I disconnect the air.

I don't believe the issue is with my tank, as I have another classic valve mag that works great on it. It's honestly been years since I've actually tinkered with a mag. My "main" mag has been rock solid for as long as I have had it, so I never felt the need to mess with it.

If it matters, the mag in question has a am/mm splash rail, centerfeed twistlock body, and a ans reg (I don't have the matching reg body).

Any help would be greatly appreciated.

[ATBen]

Is the sear in the grip frame worn or rounded? Try to file it square or replace it if it is. Take a look at the on off pin too.

[Jordan]

Put the stock spring back in and turn the velocity up. Sounds like you don't have enough pressure returning the on-off.

[Drachen]

Ok so I tried to turn the velocity up, but I got about a 1/4 turn and it bottomed out. Tried it again after that and it was still doing the same thing. I tried changing out the reg body from the and phase 2 to a classic and its now not uncontrolled, and it stops going full auto when I let go of the trigger.

The lip of the bolt seems awfully chewed up all the way around. Could the sear just not be catching the bolt? The sear looked ok, but maybe that needs to be replaced along with the bolt?

[Drachen]

What am I looking for in the on/off pin? I have two in my tool kit.

[AnarchicArctic]

Check the orientation of your on/off pin. If you install the pin upside down, it goes full auto

[LA.Loic]

Is it possibly an ANS bolt? You mentioned the lip being worn. I’ve had a worn ans phase II bolt give me problems, like firing multiple shots before catching the sear. Try running it with the bolt from another mag.

[Drachen]

So I think I figured it out. Apparently all o rings in the on/off assembly need to actually be inside the gun in the right spots.

The little white o ring at the top of the valve was gone.

Took 10 shots before I ran out of air, but it didn't go all crazy.

Am idiot...lol

[Axel]

I promise I've done stupider than that