UPDATE
Rifle is done and i have gone through barrel break in and my first ladder. Results so far:
All results are with Hornady 175 ELDX bullets, cci 250 primers, and RL 25 powder. Hornady 300 PRC data for 175 eldx states that 83.7 is the max load so I decided to start 5% below and go up. I like to run PROOF barrels hot. They seem to like it in my other PROOF barreled rifles.
- Laddered multiple charges 79.5 - 79.8 - 80 - 80.3 - 80.6 and started seeing pressure at 81.0 so I stopped there. Decided to go with 80.3 which Magneto speed chrono showed at 3240 with around 12 FPS SD's (this should get better after firing all the brass and sizing to chamber)
- Experimented with jumps starting at .010 down to .002 and found that at anything closer than .004 started to show pressure
- Shot a couple 5 shot groups with 80.3 RL25 with .006 jump and got two sub 1/2 MOA groups (better group was .36) at 3241 FPS avg - no real pressure issues, maybe a tiny bit of extractor marks (I mean tiny if you look really hard under good light) using Hornady brass I am ok with that
So far I have 35 rounds through the rifle and with the PROOF barrel I expect it to get a bit better as I reach 60 in round count. At 60 is where my other PROOF rifles start to really group and it may pick up 10-15 FPS speed as well.
So far pretty happy. Dont think I would run a bullet bigger than the 175 in this rifle. Why? it is already seating pretty deep into the case. If you do want to run the 195 berger you may want more free bore to accommodate (I built a 7-338 Norma so I could run the 195 berger to max velocities) It was my choice to optimize this 8.44 twist rifle purely for hunting using the 175 eldx - I wanted max speed and so far it is meeting expectations.