Done lots of reloading with the 6 creedmoor found this to work across a different barrels. I shoot 1000y
115 Dtac
44.5 H4831sc
Lapua small primer brass.
Cci small rifle primer
I found less neck stretching with 4831sc over h4350. On slightly warmer loads with h4350 I was doing lots of trimming. I have shot 0ver 4000 rounds of 6 creedmoor I am now on my 4th barrel, I have a lathe so I do do my own barrels and I change them out more often than I need too. H4831SC also seems to have less throat erosion. I found 4 grove 1/7 shoots better than a 5r 1/7 a friend an I went through 4 5r barrels (thes were done by a reputable gun smith, this was at the start of me getting my lathe ready for chambering) trying to like them in the 6 but no dice. Not sure why. And we tried so many loads. We found they did shoot if we slowed the speeds way down, often below the starting list load. In 4 grove we went above the max load and we still were accurate.
I tried Hornady brass for fun 3 reloads before the pockets became loose using h4350, never tried h4831sc in hornady brass.
For mid range shooting I found Berger 105 BT to be an outstanding performer often finding large accuracy nodes that I had to shoot out to 400m to find "the load".