John,
These holdopens look so simple, but there can be some off beat problems with them. Today I ran into a really strange new one.
I had pretty much eliminated my early holdopen problem, I thought, by correcting a weak holdopen spring. Then I began getting a premature holdopen after the seventh shot, about two out of three mags; never got it earlier. Really weird. Had to take the gun home and study that one, to see how the holdopen could possibly be actuated after round #7. It took awhile.
Turned out the original German magazine had the front part of the right feed lip bent upward only slightly too much. Feed still worked just fine, but after the seventh round was fired, the eighth round (all of them, actually) was being allowed to rise maybe .010" to .015" (a guess) too high. This allowed the follower button to sharply tap the holdopen upward only a few thousandths, but still enough so that, part of the time, it could catch the bolt;barely.
Each time it did so, all I had to do was pull and release the toggle and the last round would feed normally. This meant the holdopen spring was pulling the holdopen down to where it should have been. Strange, strange, strange.
You wouldn't think this could happen. But we have to remember how firing pins work in modern designs like the Beretta 92. The hammer only drives the rear of the pin a few thousandths before stopping against the rear of the slide face. This is a safety feature, so the pin does not rest against a primer when the hammer is down. But a full hammer impact is enough to drive, bounce, the pin very far forward against its spring and dent the primer. Apparently, the 8th cartridge in my magazine was rising fast enough under spring pressure to do something similar. Or else it was black magic.
