Stumped and need HELP!

[AntsRick]

Pretty sure we have a winner here, something going on with the seating die

^^^^ditto^^^^

Not having seen a solution declared by post #28, I'm thinking this as well. I created this problem in a Marlin 338 ME with too aggressive crimping; subsequently procured a Lee factory crimp collet die & problem solved.

 

[Dean2]

It would be really polite of the OPs who ask for help on these threads to come back and post what the final outcome is. Remote diagnosis is pretty tough, guys spend quite a bit of time trying to help, and then no satisfaction from their point of view. Good for the OP though, so it surprises me how few guys have the couth to report back..