I was trying to reload some 300 Blackout subsonic ammo last night. I had to stop after 3 rounds because the bullet seating die (from RCBS FL die set # 22401) started crushing the cartridge in the neck area. The deformation was uniform, almost like the shell was too long, so I don't think it was foreign matter. I had used the proper Lee case length trimmer to get proper length, verified with a Wilson headspace gauge. The die was set in the press as instructed: screw in until touching top of shell holder with press all the way up, then 1/8th turn more. The bullet seating plug screw was all the way out, and I was slowly turning it in and checking the O.A.L. of the rounds after each turn: I wasn't anywhere near the correct seating depth when this problem started.
I gave up after trying a few die adjustments, now I have four or five bad rounds that I'll have to unload and toss the brass.
What might I have done wrong? Could a brand new seating die have such a major problem internally? Could this once-fired brass be weak enough to cause this?
I gave up after trying a few die adjustments, now I have four or five bad rounds that I'll have to unload and toss the brass.
What might I have done wrong? Could a brand new seating die have such a major problem internally? Could this once-fired brass be weak enough to cause this?