brass getting crushed during bullet seating

[darth_ritis]

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?

 

[former naval person]

Baad juju. Turn the seating die out one turn, then put a piece of brass in the shell holder and run it up. Turn the seating die down until you feel resistance, then back it off/out 1/4 turn and lock it. Then seat a bullet to your depth. Your seating die is presently adjusted too close and the case mouth is being pushed back, crushing the case.

 

[darth_ritis]

Ah, good idea. I guess I wasn't thinking clearly at 1:30 this morning. ("Well THERE's your problem!" - Mythbusters)

 

[roggom]

I think you may have read the instruction for the sizing die. The seating die you put in a case, push it to the top, then screw the die until it touches, then back it out a turn and lock. Ive crushed some before on a 7x57, just a learning experience

If it does not work out let me know, you can borrow my Hornady die set 300BLK. Im in Firestone.

 

[darth_ritis]

I think you may have read the instruction for the sizing die. The seating die you put in a case, push it to the top, then screw the die until it touches, then back it out a turn and lock. Ive crushed some before on a 7x57, just a learning experience

If it does not work out let me know, you can borrow my Hornady die set 300BLK. Im in Firestone.

We have a winner! OK, no more reloading in the wee hours of the morning, got it. And RTFM.

Thanks for the offer, neighbor!

 

[bigedp51]

We have a winner! OK, no more reloading in the wee hours of the morning, got it. And RTFM.

Thanks for the offer, neighbor!

You were seating and crimping at the same time and over adjusted so you were seating, crimping and crushing with one pull of the handle.

 

[darth_ritis]

After reading the manual and adjusting my die properly, I was able to load all my brass correctly in about 15 minutes. Rookie errors, gotta love 'em!