Creating New STW Brass from Peterson Basic

[Murtfree]

I found my new 7 STW load is a bit on the hot side and I'm losing brass due to loose primer pockets relatively quickly. Since 8mm rem Mag brass is getting hard to find, I thought maybe I should try using Peterson Basic Mag Brass and try forming from that. I know Peterson Primer pockets can take some abuse and since I bought a box of 250 a few years back to make 375Ackley brass, I thought it may be worth a shot since they are only collecting dust. My question is how to go about forming them to keep brass loss to a minimum. When trying to form 375 Ackley brass I never was able to perfect the process and deciding to just fire form standard 375 H&H Brass. I'm sure there must be a number of sizing steps to get from straight walled brass to a 7mm neck. Peterson claims you can form almost anything down to .264 Win Mag. I will call Peterson for advise but thought I may as well start here and pick some brains.

 

[Murtfree]

After much digging I stumbled across the answer to my question. I figured someone may have tried this before but didn't find this thread in my initial search. Posted the link for others; read to the end to discover the exact process as well as other options. I now know why I couldn't form 375 Ackley brass from it. The necks folded, so now I purchased a used set of 416 Rem Mag dies on the cheap to start the forming process. https://www.longrangehunting.com/threads/peterson-brass-belted-mag-basic-unprimed-box-of-50.296252/