Backed out primers can indicate a headspacing issue. Handloaders have been known to compensate for excess headspace to a degree by backing out the full length sizing die slightly to reduce the amount that the case shoulder is set back. That makes me wonder, aside from checking the headspace of the gun (we know norinco's can be sloppy), has anyone also tested the headspace of different brands and lots of factory ammo?
I have, I've miked a lot of ammo. most are bang on SAMMI spec or a little under.
I just put 20 piece of MFS in the Mic, 18 were bang on 1.630 (go gauge) 1 was 1.629 and one was 1.628
I get the same story with norc, hornady and AE.
The manufactures are prett stringent with this
I keep saying "this is a head space issue, the op confirm on page 1 the head space went from unable to chamber a .308 no go gauge to almost chambering (less then a thou off) on a 7.62 field gauge that's a movement of 15 thou or about 1/64th of an inch in less then 100 rounds.
People keep blaming the ammo, but I would bet the people that had the same thing happen in their norcs have excessive headspace as well.... some ammo; especially the cheap ####, just can't take that extra stretch.
They came up with these specs for a reason, I don't get why some members here advocate that its not a big deal to be out of spec. To just keep shooting.
I fired an out of spec round unwittingly (out by about 10 thou in COAL), and the gun grenade in my face and peppered the firing line with bits of the rifle.
If a gun chambers a no go gauge, it need to be fixed, Field gauges aren't "oh i guess its ok" it was meant to be a IN WAR measurement (in the field) were it would be considered an acceptable risk to allow the soldier to keep firing (as opposed to going without a weapon) it till it could be replaced or repaired ASAP. If a weapon chambers a field gauge it considered so far out of spec that it was to be removed from service immediately regardless of the circumstances.