My personal proof barrel on a trued Rem 700 in 6.5 shoots 1/4 moa and I have shot 5-6 Proof rifles in various cartridges, all shot 1/3 moa and better up close and far in good conditions
I've got a build in progress right now for a switch barrel in 300 WSM and 6.5 SAUM. Both will be Proof Barrels. I've only had one and that was on a 338 Lapua. That barrel was very solid and would shoot excellent groups. The reason I like the Proof barrels for hunting rifles is because I've pretty much switched over to only shooting suppressed, and the larger, stiffer barrels handle the weight of the suppressor better without having to add a lot of weight.
My first screw on barrel. Proof Research Carbon. 28" 1-8 twist. Long action 6.5x284.
Checked my go and no gauges several times. Put gloves on and pulled the trigger...everything worked...whew...
Posting a picture of shooting Nosler 140 gr RDF bullets...
The first 50 rounds...as I laid down the copper, the barrel got better...never cleaned it...never did any "break in"...
The last group is the top left hand corner...RL 26 @ 3123fps with an ES of 13. No pressure signs...Got cold and dark...went home...not sure if I want more fps...Yah right...
I have one on a pierce action 6.5 creedmoor that also shoots amazing. Load development was about 50 rounds. Also purchased one for my 7mm blaser build that should be done in the next 2-3 weeks. I also visited their facility in Montana and it's top of the line in manufacturing. It's pretty amazing. I have visited a few other manufacturers and their facility, machines and processes are state of the art. Purchase with confidence.