Home Forums Hunting & Shooting Hunting Rifles 308 Twist Rates

Is 1:8 to fast a twist rate to shoot 168-175 in the 308, what's your experience?

Mine has an 11 twist and shoots those just fine out to 500yds. I guess if you’re gonna go out to 1000 a faster might help but I have nowhere to shoot that long. If I were going to go to 1000 I’d probably go to a heavier bullet to get the BC up.

I have a 9 twist and it shoots the factory 175 Federal SMK sub MOA. Hit steel at 600 easily but wasn’t measuring groups then. Similar results with 150 Fusions, so think you’ll be fine. Picked up some 200 gr subsonic. If it ever stops raining I’ll see how they do.

I have an Obermeyer 11.25 twist that shoots 190s just great out to 600. I've never shot it at longer ranges.

Several years ago, I read an article on a .308 with a 1:4 twist. As range extended past 500 yds., BC improved, as well as accuracy compared to a 1:10 twist. Of course, I can't find it now, either in print or in a whole couple minutes of searching on line.

I read the article a couple of days ago while researching this, I'll see if I can find it.

Some people say you can twist a 168 to fast with a 1:8, others say you can't. Looking for experience from somebody here.

The next couple 308’s I build will be 1-11”

which 168? how many 8 twist .308 win barrels have you laid eyes on?

I have one, brand new, next question.

So do I

My gunsmith (who retired about 2 years ago ) used 8 twist Kriegers on .30/06 and .300 magnums of various stripe for shooters who started going long years ago with superb results with 165gr and up bullets. 200gr Match Kings from the magnums were impressive on elk at 900-1000 yards.

Can't say about the 1:8" twist. I have a 1:10" twist 20" semi auto, and it puts 168gr Nosler bullets well under an inch at 100 yds. My 24" .300 WM also has a 1:10" and does the same with 180gr Barnes and Nosler bullets. For those anecdotal reasons, if I was looking for a new rifle to shoot .308 cal. bullets in the 165gr-180gr range, I would be looking for a 1:10" twist. Not saying others won't work well for that. Just sticking with the one that took me to the dance.

Don't just guess - http://jbmballistics.com/cgi-bin/jbmstab-5.1.cgi

Generally, a 11 twist is enough for 200gr bullets. But there are a lot of new, super-sleek 200-something grain bullets out there, so don't just guess.

If you check it out at 72F and 2,400fps MV, the Berger 200-20X is marginal and the Sierra Gameking is fine.

I thought you were headed to 6.5 Creedmoor land.


Okie John

I am building one. But also going to do at least one 308.

No downside to faster twist. Infact the bullet spins tighter and increase the BC. I like fast twist barrels.
I have a 10 twist 35 Whelen that shoots .5 MOA with Barnes 180 TTSX

There has to be.

If I'm not mistaken, faults in a given bullets construction and design start surfacing more readily in deteriorating accuracy with a faster than "normal" twist. Dunno, but I'd be curious to hear those with more experience than me speak to the point.

In the waning days of the .308's dominance in NRA national matches, I believe 1 in 11 pretty well dominated the line, any twist working across the course to 600, but the 1 in 11 I think shined in the Palma. If I was building a .308 I would use the information from match shooting, which when you boil it down is something on the order of a 120 shot group...rather than anecdotes without records to back them up.

So, I ran the numbers on some of the most-accurate combos I have, and the results were interesting.

The linked site says: “The Miller stability value … should be between 1.3 and 2.0 to ensure stability (the military uses 1.5).”

The most accurate load I have is a CorBon-loaded 225gr TTSX out of my 1:10" .340 Wby at 3,140 fps.

It came out to a stability factor of 2.685--way above the 2.0 max suggested by the link.

What is supposed to be the problem with over-stabilized bullets above 2.0?