PMC 45acp brass trouble

[joneb]

I loaded some Extreme 200gr plated RN with PMC brass. The case walls are quite thick compared to Winchester brass I loaded prior to the PMC. I readjusted the seat/ crimp die. I should have measured the case lengths, I adjusted for a shorter case .892" not knowing this brass had length variations from .890"-.897
Here is what happened when I came upon a long case,

This round would not chamber in the barrel, it headspacing off the wrinkled copper plating.
Here is the round adjusted for the .892" case length,

 

[Blue68f100]

A good reason why I use a separate crimp die.

 

[joneb]

A good reason why I use a separate crimp die.

I agree, I should have added a step with this brass, with the Win. It was not a problem. As the flare was being removed the inside of the case mouth bit into the fragile plating moving it forward as the seat/de-flare step was completed.
I won't use this brass for plated again or lead, and will pay more attention to case wall thickness of various head stamps.
I got lazy and should have set the die to a middle length. I will likely call out the long cases and trim them to decrease the length variation.

 

[horseman1]

Thanks

I've never had this happen, but this occurred because the taper crimping started before the bullet was completely seated, right? So one should set the seating die to the longest case they plan to load, trim the cases, and/or crimp as a separate operation (what I have done so far). Helpful to those of us with less experience to see the actual results.

 

[joneb]

but this occurred because the taper crimping started before the bullet was completely seated,

Normally with plated and jacked bullets I don't have this problem, I apply very little crimp. If the diameter of the cartridge measures .471" where the bullet is seated my crimp at the case mouth would measure .470". As this slight crimp is being applied the bullet is still being seated, with most brass this works. With lead bullets I seat and crimp or de-flare in two steps, this helps to keep the lube from gunkin up the end of the case mouth.

So one should set the seating die to the longest case they plan to load, trim the cases, and/or crimp as a separate operation

I normally don't see this much variation in length, or maybe the thick brass magnified things. I have revolver brass that is 30+ years old that I never trimmed, because it didn't need it, but most of the revolver brass I find recently has length variations up to .01". Perhaps new crimping methods has eliminated the need for a consistent length? But brass that head spaces on the case mouth is usually + or - .002", I will start to keep a closer eye on length and thickness