I have loaded 6.5 Creedmoor up to 6.5 PRC factory speed (Lapua SR brass). Absolutely no pressure signs at all.I tried some speciality brass with the Creed. Small rifle primers. Checked estimates for pressure on Quickload for what it was worth I mean I was going to be way above Saami. It loaded up to factory box performance on 65 PRC. It’s not rocket science. I assumed that the safety factor on the rifle design was a whole heap more than about 15% over a theoretical Saami max p.
What is clear is that Creed factory ammo is way under loaded making room for a nice magnum cartridge.
Last time I heard there was a suggestion that the 277 Fury was being downloaded from 80ksi as it wasn’t very accurate
I also have a 6.5 PRC that can be loaded way up above factory speed.
Essentially, you can buy standard factory ammo for both, or load for both, and retain a 300fps difference. Or you can load for Creedmoor and obtain factory PRC performance.
Mixing across both rifles with both factory and loaded ammo gives me a range of speeds from 2550 to 3150 for the same bullet. Very handy to have that flexibility, so I can choose rifle and load to fit the context.
Roe at short range in woodland? Creedmoor with factory ammo. Sika at long range in clearfell? PRC with home loads.
