McGowan steel has nothing to do with this issue. You are shooting a lot of powder.
Now you start to understand the importance of throat geometry on a new chamber(reamer design), Max OAL of magazine, plan accordingly.
Measure your leade growth on a regular basis.
Yep. I'd be interested to see how the PRC compares to the creedmoor in that department. I'm thinking the PRC is going to be more like the old 264 winchester though. My Creed has burnt its throat back .025", but after 1,140 rounds downrange....and that is a cheap azzed rough savage barrel to boot...