Just got 100 new unprimed Lapua 7.62X53 R to shoot from my M39. Carefully prepared them (cleaning, FL sizing, another cleaning) and load 50 of them with Rem 9 1/2 primers,19 gn of #2400 and Lee 160 gn (real weight 168 gn GChecked) and went to the range. And see what I got after shooting:
From left to right: 1 - old PPU (19 reloads) and the rest all Lapua. I shoot 104 rounds that day (54 PPU and 50 Lapua) from same gun, same primers/powder charge and same bullets, but 35 Lapua cases got bulged on the shoulders. The rest of Lapua looks like second one on the picture. And everything okay w/PPUs. I checked that load in M39 many times (from 16 gn to 22 gn of #2400) w/PPU brass and nothing similar. What is that? Too short to ogive brass? And BTW new brass length is 2.087" and once fired - 2.076/2.077".
Is it safe to reload and shoot again?