450 Bushmaster case head expansion question
Posted: Sun Jan 07, 2024 6:26 pm
I reloaded my first 450B rounds today, I chose to start cautiously and work up as I've learned to do with other calibers. I loaded new Starline cases with 35.0grs. of Lil'gun, 250Gr. Hornady FTX bullets, lit by CCI 400 primers I used a Lee factory crimp die set to .477", my C.O.L was 2.225". Everything went fine, all the rounds chambered, fed, and ejected at 3 O'clock 6' away. I have a few pieces of Winchester brass from the factory rounds I bought to get me shooting, I loaded the exact load in the Winchester brass and shot those as well. The first thing that got my attention was the ejection pattern, it was all over the place, one went straight out at 2', another at 4:30 at 8' and one somehow went to my left at about 2' away. I picked up the brass to examine the primers and they looked good, but the shiny ring at the head of the case got my attention. I took them inside and did some measurements and they expanded from .393" to .397'. This seems excessive to me. Am I worrying over nothing here or is this a bit much? I measured the new Starline cases and they are .397" at the head right out of the bag. If you have any suggestions I welcome them, Thank you