It takes a noticeable difference in seating pressure to have it be the cause. Is it the same batch of powder and primer as first load? I think all the other replies have it covered. If everything checks out, back down and rework load.
No i have had this gun for 35 yrs. Been loading this same gun the whole time. I was having trouble before but it was all old cases. New cases still blowing out the primers. Cleaned bore out not long ago.
I just did the water test, filled both an old and a new case and the new one is bigger. If I did it right, I weighed them with water and new is.4760 oz.,old is .4630 oz. I never heard or tried this but there it is.
Primers are gone when I open the bolt. I went below lowest data load but read that going below is not good either. I think I read that on this forum from years back. So I'm not doing that. As it is I went to 32.0 which is .5 below Speer's load for 4064 and had the same problem. I did take it to a local GS who I had never been to since I don't know anybody here, and he didn't see anything wrong with the gun,chamber, bolt. I am going to buy some factory stuff and see what happens.
I assume by old brass that you mean they had been fired several times.Is it hard to run them thru the sizing die after firing? Do they require a lot more than normal trimming? If your brass has always failed prematurly then I would say you have always had an underlying issue with your rifle,and maybe this new batch of brass is a hair thinner,or softer,and fails the first time..I overheated some brass during my first attempt at annealing,and the primer pockets stretched out,and the primers fell out when I opened the action..I doubt you would anneal new brass though..Do you know who built your Mauser?,and what manufacturer the barrel is from?..I know if you have too much headspace,or oversize chamber it s hard on the brass,but I don't know how it would cause the primers to blow out..Unless you have a real high dollar barrel,and if I was in your shoes I would probably have it rebarreled,before I put of with too much grief from it..
No the cases started failing recently. Some of the cases I have had for years. I did buy a box to get new cases but that was within the last 4 yrs.I have been shooting more since I retired and I did anneal the older stuff but the old brass was failing in the last year. I have had cases fail over the years with cracked necks,cracking just up from the rim. This was not that often so to me they were just worn out from being reloaded too many times. But now with the primers being blown out with never fired cases is just crazy. I went to a gunsmith here in Springfield and he took a case and put tape the the primer end of the case and said it didn't show any problems with head space. He said it was good that way. I would love to get it back to the guy in NY that built it but I'm 1200 mi away. We'll see, I have some more places here I may take it to . I may try factory ammo first.
Very good advice thank you. Not that the others aren't just good advice.
I just went and looked again because I've been going over and over the situation and it's older brass and once fired new stuff. The new brass has stretched primer pockets (win) and older brass (Rem) either sort of flattened primers or primers blown out.One question going through my little brain is could there be too much neck tension? Also even though I'm below max length (2.350") at 2.343", could I still be too long.I am going to try '243's idea and load 3 rds. at 31.3 and see what happens. So frustrating!
