This is not good news if the barrel has not been stress relieved. You may have a warped barrel which changes POI when warmed up. Sorry to say this...

I already indicated that the issue was fixed by training the operator.

Did not notice this...but will wait till the hangover is gone....

Glad to hear you figured out the problem, svandamme.

Just for shirts and gurgles, in case this problem ever comes up again with another shooter, svandamme's situation sounds like a classic case of anticipating recoil. That causes most shooters to dive forward, hence a low shot. After a few magazines full, the shooter gets more relaxed and no longer anticipates recoil, then the shots come up to the POA.

Just a thought based on his description of events.

Ken

My take is that when the gun.......and you......are cold.....poi will be diferent. Once you warm up.....not the gun....that is the diff in poi. Try having a friend warm up the gun for u....then shoot it urself..... Post the results for us?

A good suggestion for ruling out metallurgical factors.

The only time you'll see a cold-bore change of impact is in a long-barreled gun like a rifle and normally, it's usually the first round out of the tube.

I think your grip loosens a bit when you get a little tired from gripping too tight and anticipting the recoil, allowing the muzzle to flip more. Warming up with another gun gets you past the too-tight grip phase.

I've noticed the same phenomenon, using a 22 first improves my groups considerably.