Re: 338 Edge Bertram brass
Dan, I just went through the same thing. I had a firm bolt close on the new brass first time, so zero head space. I feel this was part of it. After the first sizing I bumped the shoulder back .001 to .0015" and they then chambered with an easy bolt close. I have now fired this brass 3 times and no more ejector pin marks. In fact I am seeing the marks from the first firing fade away. I got these pin marks while seeing no flattened primers. I have since raised the charge up 1 1/2 gr and now am just getting a slightly flattened primer. So I feel I am at max with 92.5 gr of H-1000 and a 300 gr Berger OTM.
Did you have a firm bolt close the first firing?