Yeah, I only shoot Remington brass in my 300wm and in my 260 Remington and I absolutely love it. Maybe I just got a bad batch. I can't explain it either but I went with Norma and have had zero issues.
I'd skip the Bertram 300 RUM too. It's the most inconsistent brass I've used, and the primer pockets aren't holding up any better than brass that costs 1/2 as much. lt's not what I expected to get at $2+ per case. I'll use this batch up and switch back to Norma or try ADG.
I have a handful of ADG brass in 300 rum if someone wants to try them. My friend gave them to me as his min saami neck wouldn't clear without neck turning which he did not do.