Most (if not all) of my 308 loadings are for my Super Match M1A. It shoots 175s great at the normal 2550 area. But in a bolt gun you could get a bit faster.
This should give you an ideal. In working with my granddaughter in her science project, we cut a 308 barrel down 2 inchs at a time to 16 inches to see what the differance would be. We used Hormandy factor 180 grn cor-locs (the project was about hunting rifles and energy differant barrel lengths). Here is a look see, I would think you could get simular velocities with the 175s.
The first col. is barrel lenght followed by Vel @ 100, KE @100, Vel @ 300 and KE @ 300 yards
My "hot" 1K accurate load in a 20" factory Rem 700 SPS-T barrel/chamber is just right at 2610, while my normal load is right around 2550. I've load tested up to 2650, but was starting to get some pressure signs and poor accuracy up there. With a tighter custom chamber, I don't think its a problem to get normal loads to 2650, <span style="font-style: italic">maybe </span>2700.
I manage 2720~fps with a 175smk and 45gr of Varget in a lapua case from my 20" AIAW (factory barrel). Wind and drop wise it is a very different game then I used to play with Berger 155.5s @ 2950 out of a 24" AE.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: LVMIKE</div><div class="ubbcode-body">I manage 2720~fps with a 175smk and 45gr of Varget in a lapua case from my 20" AIAW (factory barrel). Wind and drop wise it is a very different game then I used to play with Berger 155.5s @ 2950 out of a 24" AE. </div></div>
Holy crap! I didn't know you were getting that high of speeds out of your AW with that load. I shoot the exact same loading and I'm only getting 2600. Maybe when my gun gets back from SAC, it will do much better after he re-reams the chamber. Should be much tighter than the factory Rem chamber, that's for sure.