[quote]ORIGINAL: Pawildman

As far as case stretch goes, smoking a fired case and setting the resize die as Eldeguello suggested should take care of the problem.
As far as the dimpled case goes, from what I got out of the original post, the case was NOT dimpled before firing due to the die being set excessively low. If this was the case, all or most of the cases would have exhibited it before firing. .The dimples appear to have occurred in the chamber upon firing and the case rupturing.[quote]

Most likely rom low chamber pressure due to gas escaping when the case ruptured....


(I've been using R-P, Winchester, Norma, and GI brass now since about 1954, and believe me, they all make some bad stuff once in awhile. Case neck splitting is due to lack of proper annealing. If this is happening with R-P cases, just anneal them before you load them. I've never had any R-P cases with oversize primer pockets - but I have foundsome WW cases that had off-center flash holes. (In factory -loaded .375 H&H ammo......)