M38 Mauser
I was shooting higher velocity, pushed it to 43gr but there was a stiff bolt and marks on the head, just not good.
There was never a plan to hot rod the rifle, just get a good group and reasonable velocity.
The part that is astounding to me, based on the BC of the bullet, there is almost no velocity loss with the 143gr bullet, holding energy like crazy and still giving me that 400 yard deer rifle I was working on.
That's the beauty of long/heavy for diameter bullets.
Good for you on not pushing that M38. They're very strong but I've had one of mine blow off the receiver ring and seen a few others with similar failures.
My fault, with my rifle and the other rifles failed for similar reasons. The extra hundred fps isn't worth it.
I will admit, the rifle was pushed to the kaboom point, mostly as an experiment. It was from a batch of rifles that first came into Canada back in the late seventies. I bought them 50 at a time.
The Swedes sold of their best rifles first and followed with the mismatched pieces several years later.
The rifle I kaboomed, was in excellent condition, likely refurbed and put into long term storage immediately after.
The hotter I loaded it, the better it shot. I kept increasing the load with two different bullets, 160 grain, round nose, flat base and 140 grain flat base, spire point.
There was also another issue, at the time proper cases were next to impossible to get, unless you could find some old Dominion loaded commercial stuff sitting on dusty shelves. I fireformed IVI 7.62x51 brass, after sizing down the necks. This resulted in a cartridge with a neck about half as long as it was designed for.
Whether this had anything to do with the kaboom, I don't know. The South African Boers had a similar issue with some of their ammunition that had been remanufactured from a shorter cartridge case, with resulted in shorter necks.
My magic kaboom load was 55 grains of #44 powder (3031) over CCI 200 primers, under the 160 grain bullets.
The rifle was tied to an 18 inch tire when it failed. I was curious, the rifle was cheap, even for those days. 50 at a time cost $17 each, delivered. I was actually comparing it to a Type 38 Japanese carbine that had seen better days, with a ground off mum and lots of rust, with a poor bore.