So far I have 65 rounds on the new 308 barrel on long action origin. Most rounds I have fed through the hs precision 30/06 mag. It feeds fine so far as long as I don't "baby" it. I only have 11.25 twist and 26" total length so long freebore won't benefit me much.
Main purpose of this action is 300winmag for hunting. Secondary purpose , I needed a 308 to shoot in a local match so i repurposed this action in off season. No regrets so far. It's feeding well and shooting well. I'm planning on load development after 100rds. So far I'm shooting ammo I had for a different barrel a couple years ago.
Here are some loads you may benefit from with your 308. You will find that most are not far from Dan Newberry's OCW loads for 308 though I did work them up completely in OCW format to begin with. They have been really good & consistent in my 12 Twist 308 26" varmint profile Remington 700. Some of these can get me to 1000 at 34 ft above sea level but are quickly running out of steam at that distance. I have some more 308 loads that work well in my 7.62 x 51 chambered AR with AR Comp and 168s
I added a Wyatts bottom metal and mag to my 700 to give me a little extra OAL capacity.
1. Win brass. 46 grains Varget, Federal 210 M, 168eldm seated 2.857. Runs 2715fps or so. My barrel seems to be a little slow. That's the velocity where all the dope fits in my ballistic charts and what my chrono gives me. I always back calculate to double check.
2. Win Brass, 45.7-8 IMR 4064, Fed 210m, 168eldm seated 2.857, 2740 velocity. Both of these loads give me single digit ES and SD. As you can see the 4064 load is a touch quicker and I have to dial back slightly when switching from Varget. Both may be a bit warm for high fire rate tournament work but if you are seating farther out they might be fine.
3. Neck Turned LC 85 match brass, 42.8 imr 4064, Fed 210m, 168 Amax seated 2.81. I forgot My velocity number but it's a good shooter. Closely mimics charge weight and performance of Fed, Gold Medal. These may be close for your heavier, thicker walled cases like Lapua.
4. Neck Turned LC 85 with 41.6 grains of H or imr4895, 168 Amax seated 2.81, or truthfully almost any 168 grain bullet, Fed 210m. Around 2600 or so IIRC. Good Shooter but just keep a close eye out for pressure when working up.
5. Really good hunting load. Winchester Brass, 46.6 Varget, 150 accubond seated 2.82, cci200, 2900fps, single digit stats. Tack Driver and boringly accurate load.
6. Neck Turned LC 85 match LC84 brass, 43 grains of IMR or H4895, Fed 210m, 150 accubond seated 2.82, 2900fps. Very low stats, Good load up to around 500 yards for deer And hogs.
Some of these loads should be considered hot. But they show no pressure signs in my rifle. Always start low and work up. Being able to seat bullets out longer, plus the long throat in this riflle, allow for somewhat increased charge weights. These loads are safe in my rifle, they may not be safe in yours.