I am looking at maybe setting up a 308, but I see some models have a 1-12 twist, while others have a 1-10. I think Tikka even has a 1-11. Will the 1-12 twist stabilize most 180gr bullets, or would I be limited to the 165-168gr due to the slow twist?

1 in 12 will stabilize 180s just fine.

My Remington 700 with 20" tube stabilizes the 180gr Hornady SST just fine.

Pretty sure all Remington's are 1-10.

Given 1) how well made ALL bullets are now, compared to the ancient 1-14 twist past, and 2) the preponderance of extra long high BC and/or monometal bullets, why the hell would anyone use a long twist barrel?

I shot a 1:12 300 Saum for years. It was a hammer with 180 accubonds. If starting with a blank slate I’d twist it faster but wouldn’t sweat a 1:12”

If it's me I would twist it no slower than 1:10 but that's just me and I'm no barrel maker. And even though I probably wouldn't shoot any bullet heavier than 180 grains in a .308 Win. I wouldn't want to handicap the rifle either just in case I might want to shoot something heavier in it.

Nope

My 308's have all been 1-10 or 1-12. All have shot 180's well. Were I barreling a 308 tomorrow, I'd go 1-10 or 1-11.

Bore rider .300"
Driving bands Sized to .309"
Weight 231grns
Length 1.25"

Stable just fine in 10" twist Bbl.............

300 Blackout, Contender 18" Bbl..............

Calculate your own:

http://www.jbmballistics.com/cgi-bin/jbmstab-5.1.cgi

Other than the very long VLD BTHP 180's, you'll not have any problems fully stabilizing a 180gr bullet in a 1:12 308.

There is no down side to 1 in 10. I have a 1-11 and it won't stablize barnes 175 grn LRXs even the calculations say it should.

My ADL Varmint is a 1:12

I had a BDL Varmint back in the day with the 12 twist, and would would spin a 190 SMK just fine.

Of course, it's about length, not weight, of the intended bullet.

My buddy's vintage Browning semiauto I'm sure has a 1:12 twist. It won't shoot 180's worth a hoot. It'll do an inch and a half with most 150's though.

I've got a couple 1/12 308s. mine both do fine with 208 Amax, 200gr SMK, 210gr Berger.


Here's some targets with the 208 Amax,

10 rounds at 100 yards, 0.65" center to center.


4 rounds at 560 yards, under 4".


6 rounds at 1120 yards, about 9".

In my limited experience, it depends on length of barrel and speed your pushing the projectile. If I were putting together a .308 build, and I am, I’d probably just go 1-10”. I shot with a Team USA/F-T/R member and good friend. He was pushing some long hybrids before most had access to them. His rifle had an 11 or 11.5 twist and he pushed them hard out of a 30 or 32” barrel IIRC. I asked why he wouldn’t just go to a faster twist instead of struggling to stabilize at all altitudes. He answered he preferred not over stabilizing or wasting a FPS or two possibly from it. It’s been a long while but it struck me how far he’d go for the tiniest perceived advantage. He held some NRA records and was in a few Precision Shooting mags at the time so it worked for him.

I’m just going to go 23” barrel and 1-10 twist to keep it simple.

Details on why he ran that twist may not be perfectly precise due to my memory not his expertise. It was 15 years ago and I’ve since bounced off the windshield of a car making pre-impact memories foggy.

Can't go wrong with 1/10. That's my choice too on a custom barrel.