range report_m39b_more handloads and..

[_N4Z_]

More handloaded 7.62x54r and my 1942 Finn m39b.
All PRVI brass, all CCI LR primer, all 3 shot groups @ 100 yards.

Sierra SP ProHunter 180gr / 46gr IMR4320 = 1-7/16"
Sierra SP ProHunter 180gr / 48.1gr IMR4320 = 1-11/16"
Sierra HPBT MatchKing 174gr / 48.1gr IMR4320 = 2-1/8"

Sierra SP ProHunter 180gr / 48gr IMR4350 = 1-5/8"
Sierra HPBT MatchKing 174gr / 48gr IMR4350 = 5/8"
Sierra HPBT MatchKing 174gr / 48gr IMR4350 = 11/16"

The Sierra MK with 48gr of IMR 4350 looks like the tops. Going to load more of that and see if those group sizes continue.

Which brings me to a question/concern. During the shooting of the above groups a couple pieces of brass suffured odd deformation, and I am not sure why. These were all neck sized cases matched to the rifle, and on their 3rd or 4th firing.

Here is a pic of the pucker. They are the only 2 of the 18 fired that this happened to.

Any ideas?

 

[stubbicatt]

Oil in the chamber which dieseled at that point?

I've never seen anything like that.