I got a 527 in 7.62x39 a while ago. I like it quite a bit, its accurate and I havn't had a problem with it yet shooting Wolf. I got a hold of some dies for it and made a few loads with 26-28 gr. 1680, 125gr Sierra bullets and both CCI and Winchester primers. The first, win primed left just fine, the second took 2 trigger pulls, and I noticed the entire primer was protruding .015" which is something I would have definitely caught. It didn't show any pressure signs and was 26 grains of powder. I didn't shoot any more Winchester primed. The CCI didn't fare much better, 1 round took 2 strikes and another didn't fire after several. I put the 527 away for the day.
I've heard some places where people seem to think its the firing pin, some think its SAAMI specs differing from com-bloc specs. I sent an email to CZ-USA explaining the problem, asking what I could do to keep my dies, powder and bullets from being useless and havn't heard from them. Does anyone have any ideas?
I didn't know whether to post this in the reloading or not, if the moderator thinks it should be then I can repost.
Last edited by Muddog; 11-03-2008 at 10:40 PM.
Reason: not sure where to post
I'm leaning towards the cases possibly being sized down too much in the sizing die. This would allow the firing pin to drive the case deeper into the chamber (ie: excessive headspace) without detonating the primer. The dimensions between ok and not ok are very slight, just a few thousandths of an inch. How do the fired cases look?
I didn't trim the cases before loading, just full length resized. They havn't been fired either, but they are all right at that .015" short of Hornady's case trim length. I'll put them through the SKS and see if that won't stretch them a bit. Thanks for the idea.
You asked about the fired cases, they look fine. You said the sizing die pushed the shoulder back, as in gave the shoulder too much angle? If that is the case, that is a problem in the die, right? I'm fairly new to reloading, so don't throw too much at me at once.
It is most likely an adjustment problem (IMO). Try sizing a case and then chambering it. Then screw the sizing die out 1\2 turn and try it again with a different case, record your results. Repeat until you can feel resistance when closing the bolt and see where you're at with your die setting. If you're way off from the recommended die setting, your die or shell holder may have been machined wrong. If it is, try to borrow a different die or shell holder and retest.
Repeat until you can feel resistance when closing the bolt and see where you're at with your die setting.
The lockup is already very tight without loading a round, I doubt I'd notice any difference until it was too late. I looked at the 3 that did fire, visual inspection shows the shoulders were lower on the case than on unfired rounds in the same batch. I put it next to a Wolf round and the shoulder on it is higher on the case, so what your saying definitely makes sense. However, I heard back from CZ-USA and they said I should order a new striker spring (not for a CZ, for a Japanese Arisaka 7 coils removed). That does nothing for the primer sticking out, so I'm still looking for an answer. Anyways thanks for the help.
