Problem With RCBS 300 mag Die

F

forrest-hunter

New member
Have 4 brass that do not hold 180 gr remington corelok bullet after running through RCBS small base seating die - had no problem rest of brass and bullets reloaded - checked bullet diameter and they where ok -can't figure out what is wrong with brass - ran them through resizer again - still no luck
 
They need the necks annealed. The necks have work-hardened and become springy, so they aren't staying the size of the die. Small-base dies work the brass harder than standard dies, so this happens faster with them. If the cases are Remington cases, too, I'll add that I used to have this same problem with Remington-Peters 45 Auto brass. It was a combination of work-hardening and the necks being a couple thousandths thinner than most other brands so the die wasn't squeezing the ID down as far by that same 0.002". But regardless of who made them, annealing is what will fix it.
 
Unclenick is most likely correct. The other option is that the neck material has become too thick and needs inside reamed or outside turned. With a standard die, it is not possible for that to be the case, but it happens regularly when match dies are set up a certain way.
 
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