I was using a 20" with a 1-12 twist but couldn't get the velocity and range I wanted, so I had it rebarreled with a Bartlein 24" 1-11.25 I get better velocity and its easier to hit those 1K targets.
I'm getting 2650 FPS with the M118LR clone. Also getting consistent hits at 1K with a 24" Rem 700/Bartlein 1-11.25 barrel. Still not happy I think the rifle it capable of doing better, just got to find the right load for her.
Are you looking for someone local? If not I just had Eddie Fosnaugh at Home rebarrel and true the action on my Remington 700 and am very happy with the results.
It shoots flatter and you'll get out further than a 308. Its also cheaper to shoot that a 338 lapua and will get you close to the same performance with a 220 gr bullet, if loaded right. There just fun.
I have a Mark 4 ERT 6.5x20 with the H58 and love it. I have no place to shoot 1 mile but its works good to 1200 yards so i'll bet the 8.5 x 25 work great. Are you active Military or LEO? if so Leupold will offer some awesome discounts.
It happened to me too, Winchester primers were blowing out and pitted the bolt face, I have to pull down about 500 round of stuff I had loaded this last winter and reprime. I sent an email to Winchester but never got a reply, bet I never will.
175 SMK, 41.8 gr IMR4064, LC Match Brass, Winchester Larger Rifle Primers, with COL of 2.80. Shot good out of my 20in Remington 700. I gave up on Varget after I found this load.