Has anyone had any issues out of old(er) 7.62x54 surplus ammo? My boss gave me a 300 rnd. box of 1955 Bulgarian 7.62x54, and during shooting at the INGO Mosin shoot today, I had a case split near the base. The guys watching me shoot said that it didn't look too good while firing that round, too much smoke/blast near the receiver? I'm not altogether sure, but should I worry about shooting this stuff?