I’ll try to add to this thread before starting a new one. I ordered up a 300prc conversion kit for my Desert Tech SRS A1 this summer for an elk hunt. I ended up developing a load for the 220gr ELDXs using Hornady brass (all I could find at the time) 77.6gr of H1000, and CCI250s. That load had single digit SD with an average velocity of 2,850 from a 26” barrel. I kinda wanted 2900 but they were more inconsistent.
Anyways, I shot 76 rounds during load development and dope verification out to 850 yards before my hunt. Every round I loaded was from brand new Hornady brass that I did a quick pass through a full length sizing die to straighten out the necks. When I got back from my hunt, I decided to size and load all of my once fired brass so everything can be put away for awhile. Upon inspection, I’ve got 15 cases that either have a crack or look close to starting a crack at the classic sign of case head separation. A couple of them have a faint ejector mark from when I was pushing for velocity a little, but most do not. I’ve pushed brass harder than this in several other guns and calibers and have never had a concern about case head separation after the fist firing.
Obviously I have either a headspace issue or a bad batch of brass, or a combination of both. I need to track down a headspace gauge and I’ll shoot a round this weekend to compare my fired brass to a new resized one. View attachment 7730184View attachment 7730185View attachment 7730186View attachment 7730187
Well, the big picture is a bummer, but at least you didn't have a horrible failure that led to injury. It is significant to this issue that DT's have strong actions and can take pretty high pressure. I'm not a fan of Hornady brass for reloading, but I have reloaded it for a few calibers without problems. I'd be tempted to push a few primers into your failed brass and some of the once-fired brass. If you have any virgin brass, that would be good for comparison. You might get a hint about whether your reloads were a big part of the picture or if headspace was the major factor. When I'm working up a load, I measure base-to-datum unfired and fired, after sizing, then after second firing, just to find out what's happening in the chamber. I want to get to where I size the case body and neck as little as possible and still function properly.
Do what you have to do to get some Lapua or ADG brass. Good luck trouble shooting it.