I've experienced a case head separation with my RMC (Rocky Mountain Cartridge) machined 577/450 cases (two of 8 fired). The first indication was a crack
in one ejected case around the juncture of the case wall with the case head. After 3 more rounds (I should have quit earlier) another case separated
completely.
My loads were assembled 6 years ago, Coyote's recipe with C.O.W (cream-of-wheat) filler, 40 gr Goex 2Fg under a mixture of 30 gr 2Fg and 30gr C.0.W., wax paper wafer and a 410 gr cast bullet, not crimped. I have not fired this lot in my rifle for at least a couple of years. I've gotten about 3 reloads from this cohort of brass, and this is the first instance of this problem.
I've pulled the bullets on my remaining loaded cartridges and examined them without any indication of cause. The bullets pull readily with pliers and the lube is soft. The powder and cream of wheat were modestly compacted, but dumped out completely with repeated tapping of the case neck on a flat surface. I don't think the bullet or charge are acting as an obstruction to raise pressures. The cases have been properly cleaned soon after each firing and the loaded rounds were properly stored and appeared unremarkable externally. The rifle, a short lever from Atlanta Cutlery, appears near new with a tight breech lockup and a mirror bore.
Using an RCBS case guaging tool, there is no indication of impending case separation of either the just-fired cases or the loaded cases I broke down. The juncture of the brass head and the case wall is however abrupt compared to modern brass cases I've sectioned, more of a right angle juncture rather than a taper.
I was wearing glasses as I invariably do, and suffered no injury when the breech opened partially, but I felt my forehead peppered with powder grains. The grooved and sloping breechblock seems to have directed the gases and powder grains upward, instead of straight back into my eyes. When I opened the breech further, the separated case head fell into the action. The rest of the case remained stuck in the chamber, but was readily removed with the first model stuck case remover from the buttstock trap of my Springfield Trapdoor carbine and a cleaning rod. I'm glad the two rifles are both .45 caliber.
I have some previously fired Bertram Bullet Co.drawn cases to try, but am looking for any helpful advice first. It seems my best recourse is to trash my remaining expensive machined cases and try the drawn cases with reduced loads.
Any information would be appreciated.
Thanks, Max
My loads were assembled 6 years ago, Coyote's recipe with C.O.W (cream-of-wheat) filler, 40 gr Goex 2Fg under a mixture of 30 gr 2Fg and 30gr C.0.W., wax paper wafer and a 410 gr cast bullet, not crimped. I have not fired this lot in my rifle for at least a couple of years. I've gotten about 3 reloads from this cohort of brass, and this is the first instance of this problem.
I've pulled the bullets on my remaining loaded cartridges and examined them without any indication of cause. The bullets pull readily with pliers and the lube is soft. The powder and cream of wheat were modestly compacted, but dumped out completely with repeated tapping of the case neck on a flat surface. I don't think the bullet or charge are acting as an obstruction to raise pressures. The cases have been properly cleaned soon after each firing and the loaded rounds were properly stored and appeared unremarkable externally. The rifle, a short lever from Atlanta Cutlery, appears near new with a tight breech lockup and a mirror bore.
Using an RCBS case guaging tool, there is no indication of impending case separation of either the just-fired cases or the loaded cases I broke down. The juncture of the brass head and the case wall is however abrupt compared to modern brass cases I've sectioned, more of a right angle juncture rather than a taper.
I was wearing glasses as I invariably do, and suffered no injury when the breech opened partially, but I felt my forehead peppered with powder grains. The grooved and sloping breechblock seems to have directed the gases and powder grains upward, instead of straight back into my eyes. When I opened the breech further, the separated case head fell into the action. The rest of the case remained stuck in the chamber, but was readily removed with the first model stuck case remover from the buttstock trap of my Springfield Trapdoor carbine and a cleaning rod. I'm glad the two rifles are both .45 caliber.
I have some previously fired Bertram Bullet Co.drawn cases to try, but am looking for any helpful advice first. It seems my best recourse is to trash my remaining expensive machined cases and try the drawn cases with reduced loads.
Any information would be appreciated.
Thanks, Max
