I have had sudden pressure increases when shooting remington factory loaded with swift a=frames after shooting hornaday encapsulated solids through two 375's. Does any one here have any idea if the very hard hornady encapulated jacket material is causing increased friction? or other causes for the increase in pressure?

I am not able to answer your question but I had a pressure excursion that was caused by a lot of grease in a military rifle bolt main spring.

quote:

Originally posted by ireload2:
I am not able to answer your question but I had a pressure excursion that was caused by a lot of grease in a military rifle bolt main spring.

Could you 'splain that one a little more fully?

quote:

Originally posted by Stonecreek:

quote:

Originally posted by ireload2:
I am not able to answer your question but I had a pressure excursion that was caused by a lot of grease in a military rifle bolt main spring.

Could you 'splain that one a little more fully?

I was shooting two M91 Mausers with new loads. The loads were being worked up in both rifles at the same time with the same loads.
Two different starting level loads of AA 2495 blew a primer in one rifle and caused no problem in the other.
The first blown primer was my first ever in about 30 years of loading and I knew the charge weight was safe. There was one grain weight difference between the two loads that blew the primers. Two other rounds in between had been fired - one in each rifle. The in between rounds and earlier rounds on both rifle showed the normal signs of a starting load.
The rifle that blew the primer was new to me. It was a mint M91. After the 2nd blown primer I gave it an extreme going over and noticed it had a slow muted firing pin fall. Pulling the firing pin assy out, I found it loaded with cosmoline. I wiped it off and used a patch to get some of the grease out of the bolt body. Then I reassembled the bolt.
The following is not accepted procedure but I tried it anyway. I swapped bolts and fired several more rounds in the offending rifle without further incident. I eventually worked the loads up 2 more full grains in both rifles using their own bolts with no further problems.
Later I worked up loads for both rifles using 4895 with no more funny business.

This entire episode was peculiar to me because of the condition of the cases. They are smutty with gas leakage on the outside typical of very low pressure loads. Yet the primer pockets were expanded about .010. The CASES were part of 1000 SL54 headstamped USGI cases I have been forming into one thing or another since about 1970. The case necks were not too large or too long. It is hard to imagine getting a loaded case neck too large in diameter in a correct to spec Mauser chamber. Headspace was a light drag close with the bolt.