7prc would slide into a 300 chamber, likely firing pin would never hit it though, as it's a fair bit shorter, about 1.81 vs 2.12 to the shoulder, firing pin protrusion is usually around .060.
Those are pressure dents, not lube dents, why the case didn't collapse fully is a mystery, probably related to timing in pressure buildup and dropoff inside and outside of the case. I've seen those dents with reduced loads, in their case, from mouth over the shoulder, sometimes the dent progresses thru neck & shoulder curve, sometimes not, it'll skip it somehow, making that kind of body dent. Kind of irrelevent in a case separation, hard to say for sure, although some cases appear to show gas travelling up to shoulder, maybe the juncture there was still under enough pressure to hold from going over it to datum area., which is what puzzles me about why case body didn't collapse with pressure escaping the separation crack. Has to be a matter of pressure equalization & drop timing, datum area sealing and perhaps deflection of pressure back on itself, from the chamber shoulder junction, brass being the easiest way to expand into.
Whatever the final outcome, somebody screwed up bad on sizing and the fool kept shooting them, the ejector marks tell a story on firing at least a few times with them at least being too short, whoever it was, needs some help with case sizing process. Don't think it was from overly hot loads, most likely would have lost primer pockets first, before a separation occurred, and they appear to probably be OK, from .what is showing there, they don't appear to be as flat as they could, perhaps should be.
I do wonder if he's learned anything from it, somehow, I'm inclined to expect nothing much, other than a wrecked gun and probably wants to quit reloading, as he doesn't appear to be the type to stop and ask what he is doing wrong, and try to fix it.
Those are pressure dents, not lube dents, why the case didn't collapse fully is a mystery, probably related to timing in pressure buildup and dropoff inside and outside of the case. I've seen those dents with reduced loads, in their case, from mouth over the shoulder, sometimes the dent progresses thru neck & shoulder curve, sometimes not, it'll skip it somehow, making that kind of body dent. Kind of irrelevent in a case separation, hard to say for sure, although some cases appear to show gas travelling up to shoulder, maybe the juncture there was still under enough pressure to hold from going over it to datum area., which is what puzzles me about why case body didn't collapse with pressure escaping the separation crack. Has to be a matter of pressure equalization & drop timing, datum area sealing and perhaps deflection of pressure back on itself, from the chamber shoulder junction, brass being the easiest way to expand into.
Whatever the final outcome, somebody screwed up bad on sizing and the fool kept shooting them, the ejector marks tell a story on firing at least a few times with them at least being too short, whoever it was, needs some help with case sizing process. Don't think it was from overly hot loads, most likely would have lost primer pockets first, before a separation occurred, and they appear to probably be OK, from .what is showing there, they don't appear to be as flat as they could, perhaps should be.
I do wonder if he's learned anything from it, somehow, I'm inclined to expect nothing much, other than a wrecked gun and probably wants to quit reloading, as he doesn't appear to be the type to stop and ask what he is doing wrong, and try to fix it.
