Twist Rate for Short Range .308

[jlarose85]

Hey y'all, I'm looking at some proof barrels for a short range (300yds and in) .308 for whitetails. My initial plan was to go with the 20" Sendero light with the 1:10 twist but came across an 18" Sendero with a 1:8 twist. I like the idea of getting this thing as short as possible since I'll be shooting suppressed. What if any difference am I looking at here by going with the shorter barrel with the faster twist? Looking forward to the thoughts from the guru's

Thanks!

 

[Recon$$]

What are you looking to shoot as far as projectiles.

1:10 will give you 150-200gr.

 

[jlarose85]

I'm not a reloader so I'll be relying on factory ammo. I'd imagine I'll probably use something in the 168gr range since that's pretty standard for .308 and offers a lot of options. Heaviest I think would be something like the 178gr ELD-X's and the lightest probably something like the 150gr SST or TTSX

 

[Recon$$]

Think the 1:10 is your answer. I did a quick Google on a 1:8 for a .308 win those guys are pushing 200gr to 240gr bullets. You won't find factory ammo like that. I've done 212s in a 20" .308 but they were in the 2400 fps range. Keeping it short range I would shoot a 168 gr in a 1:10. My 2 cents.

 

[jlarose85]

Think the 1:10 is your answer. I did a quick Google on a 1:8 for a .308 win those guys are pushing 200gr to 240gr bullets. You won't find factory ammo like that. I've done 212s in a 20" .308 but they were in the 2400 fps range. Keeping it short range I would shoot a 168 gr in a 1:10. My 2 cents.

That's pretty much what I'm thinking, I was just curious about the shorter 1:8 twist. Proof actually lists the 18" on their website as a 1:10 but the one I found in stock at Evolved Ballistics shows it at a 1:8. Not sure which one is right but in case the 1:8 is, I was curious what that was going to do for my ballistics and bullet selection.

On a related note, how much weight do you guys think I'll likely lose moving to a carbon barrel? Proof lists both of these barrels at 2.5#. My though was that it would save me at least 1.5-2# coming from a No. 5.5 taper steel Bergara barrel.

 

[Steves1911]

8 twist works well running 220gr or heavier subsonic for supressor usage. 10 or even 11 twist is plenty. I have 2 20" bbl 308 ones a 10 the other is 11twist. Oddly the 11 twist prefers 178gr pills and the 10 twist likes 168gr pills.

 

[Petey308]

You'd really only need the 1:8 if you were going to do subsonic loads, particularly in a short barrel. A lot of guys like short barrels with long suppressors together keep the overall length down. Since running subsonic velocities, and in a short barrel, the faster twist is required to ensure you still obtain proper stability and accuracy.

 

[jlarose85]

Well I'm definitely not planning on running subsonics or any bullets over 200gr so that definitely answers that question. Maybe I can find an 18" in a 1:10 twist somewhere.

Anyone have any thoughts on the weight savings question?

 

[Hugnot]

10 twist should work fine with 125's to 180's. I shot many 168 match bullets with a 12 twist.

The 168 Nosler RDF is a real long 168, Sg values show it doing well at 2,600 fps out of a 10 twist at 35 deg. F. The old 190 Sierra MK has been around for decades, favored for .300 WM use but works well in .308's.



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[Petey308]

Well I'm definitely not planning on running subsonics or any bullets over 200gr so that definitely answers that question. Maybe I can find an 18" in a 1:10 twist somewhere.

Anyone have any thoughts on the weight savings question?

2" of barrel isn't really going to save you much weight. It'll cost you around 40-60fps in velocity. So whatever that's worth to you.

 

[jlarose85]

The 2" between the 18" and 20" proof doesn't save any weight. They have them listed as the same weight but the contours are different so that makes sense. My question was the weight savings between the steel barrel and the carbon barrel. My assumption was that I'd save roughly 1.5-2# coming from a No. 5.5 Bergara to the proof.

 

[Michael Eichele]

For the average 308 load, 11-12 twist works very well. If you want 190-200, go 10-11. If you want heavier mono metals go 8-9.

 

[waveslayer]

I run a 1/8 out of a 17" in my MRAD. No problems at all. 175 are money. 168's are a tad larger on grouping... I'm talking .4 moa to .5 moa! So get that short barrel and smoke something with it

 

[30BR]

Get the 8 twist. It won't hurt anything. Gives you the option of running real heavies at real slow speeds; possibly subsonic (?) for a really quiet hunt.