Need barrel twist advice for FTR

[Dgd6mm]

What would be the best twist for a .308? This barrel will be shot at 600 and 1000 yards. The bullet weight will be from 175 - 190 grain, anything from Hornaday to Bergers. I would like good solid advice from shooters that have done this and been successful please. If I left something out that may help in your answers, please let me know.
Thanks, Don Dunlap

 

[SpencerC]

I just recently got a 1-11" twist broughton 30" for F T/R and that will let me keep my options open right up to the Berger 210VLD's. You are not at a disadvantage for shooting lighter bullets (155-175's) in a faster twist if that's what ends up shooting the best for you. JMO

 

[jr600yd]

I shoot mid-longrange and use a 30" 1/12 barrel. I've shot many 199-200's at 600 with 190 SMK's and the same at 8-9-1K using Berger 185 VLD's. If you are going to use a shorter barrel like 24-26" I'd go with a 1/10 twist.

Most long range competitors use a twist designed for a specific bullet weight and long barrels (30 +) 1/13 or 1/12 for the 155 class 1/11-1/12 will handle bullets up to 190 grains and 1/10 for the heavies 200grs +

Nothing written in stone here just general go by knowledge. Every barrel is different. Your 1/11 should shoot everything you want very well.

 

[XTR]

I went with a 1:10 in my new 30" barrel. In retrospect I'm shooting the 185 BTLR and I'd have been fine with a 1:11 but it's mounted and shoots great so I'm not complaining..

In a TR gun you should be fine with any of the above.

 

[Steve Blair]

I shoot mid-longrange and use a 30" 1/12 barrel. I've shot many 199-200's at 600 with 190 SMK's and the same at 8-9-1K using Berger 185 VLD's. If you are going to use a shorter barrel like 24-26" I'd go with a 1/10 twist.

[br]
Jim,
You've shot cleans at 1000 in F-T/R? Were they registered matches? [br]
I use a 10" twist but only shoot heavy bullets. Previously, 210 LRBT and now, 230 Hybrids. As Jim noted, the barrel is specifically throated for 230's with a .280" freebore.

 

[Redhighpower]

I agree with what is said above. My experience was with a Winchester Varmit 26" with a 1-12 twist. It loved 175's SMK. In my first competion @ 600 I shot a 200 14X clean and that was using a sling. If shooting at 1000 yrds I would want a 30 inch barrel.

 

[DennisH]

11 twist will get the job done!

 

[jbpmidas]

I'm using a 10 twist, 28", Brux barrel. I shoot 185 Hybrids at 2660. One more match like my last two, I'll move up to Expert. I am shooting 600 yards.H

 

[Keith Glasscock]

Clean at 1000? Sling or F-TR? The current F/TR record at 1000 shows as 149/8 and 199/12 respectively.

I'd love to shoot a clean at 1000 yards in F/TR sinceI only shoot long range at registered matches. On the other hand, I've only seen it done once and that was by a member of the current F-open team with a 284 win.

 

[jr600yd]

Sorry guy's I'm a sling shooter. No scope, using Irons!

 

[Dgd6mm]

Thanks to all of you for good information that will help me in my decision. The weight class bullets that I mentioned [175-190] is that the norm for 1000 yards, or should I consider something heavier? Will a 1-11 twist do for 175-210 + grains?

 

[Keith Glasscock]

Yes, 175-190 is a common bullet weight range used for long range, but so is the 155. Some enterprizing shooters are running much heavier bullets, but the jury is still out on how well that really works.

An 11 twist will shoot almost anything up to 210 grains at reasonable temperatures. You will not have a lot of extra stability at the higher end of the weight range, but it will work. I've shot 208 Amaxes, 210 JLK LBT's and Berger 200 hybrids out of an 11 twist barrel. All worked well. I've won my fair share of 600 yard matches with the 208's and 200's in both windy and calm conditions. The downside to those bullets is the big recoil. If the recoil wears you out during a tournament, you would have been better off with 155's. The trick is learning how much you can take before your performance suffers.

If you think that you might want to give the heavies a try, a 10 twist is the same price, and it will definately shoot anything out there - including the 230 hybrid. In my mind, there just isn't a reason to not overtwist the barrel slightly. The downsides in short range precision don't apply, the increase in aerodynamic jump is really minimal and predictable, and the velocity, for all intents and purposes, is the same.

Good luck with your project.

 

[Dgd6mm]

Thanks Busdriver, thats just as I asked for good solid advice. All of you have been a big help. 1 more thing if you all don't mind, 30 inch for barrel lenght?

Thanks Don Dunlap

 

[Keith Glasscock]

Yes, 30" gives you the flexibility in powders and bullets to make 1000 yard velocities easy.

Make certain to get a profile that will make weight with your chosen action/stock/optics/bipod.

 

[Dgd6mm]

Thanks for the info.

Don Dunlap

 

[Rustystud]

Donald:

I bulid a few FTR rifles and the twist rates most frequently used for 180-200 grain bullets has been 1:12, 1:11, and 1:10 for anything heavier than 200 I would recomend 1:9, or 1:10 with a 32-34" barrel.

Just my opinion
Nat Lambeth

 

[GermanS1]

Don, I use a 1:11" twist for F-TR with 175 gr. and 185 gr. bullets. That twist will easily handle 200 gr. bullets, I've shot them in other rifles with a 1:11". The main problem as you go to heavier bullets is the throating on a .308. If you don't throat it longer you run out of powder space quickly. If you throat it appropriately for bullets of 200+gr. weight, then the lighter ones will have excessive jump to the lands. With a short-neck case like the .308, it's best to pick a relatively narrow band of bullet weight and then throat the chamber accordingly.

This has a bit of explanation and some useful photos: http://riflemansjournal.blogspot.com/2011/07/cartridges-308-heavy-bullet-conundrum.html

 

[Dgd6mm]

Thanks everyone for the replies. German, thanks for all the insight on the .308, that was a good read and very informative.

Don Dunlap

 

[Dgd6mm]

I took the info from everyone and decided to try a 1-11 twist 30" CBI barrel. This is a pre-fit that I requested from Jim Briggs to go on a Savage action. It will be chambered with .090 FB, for this is the reamer they use. I have not decided on a bullet yet. If I need to lenghten the FB, I'll do so later. Being that this will be the first .308 I've had chambered, I'll learn from here.

 

[Laurie]

Have a read of:

http://www.targetshooteronline.com/

current (April) issue available as a free Adobe PDF download, pages 68-85. You should do well with your barrel choice, although you may need to have the throat reamed out a little at a later date as you suggest.

As I nearly always do, I find myself in 100% agreement with German (his post of 25th March). For anybody looking for a good multi-purpose 1,000yd set-up that handles 155s up to the Berger 190s and 190/200gn Sierra MKs (185gn Berger Hybrid apart) a 1-12" twist barrel allied to a throat that sees the 155gn Lapua Scenar, new model SMK and 155.5gn Berger seated very shallow in the case provides excellent bullet position, good MVs and excellent results with these bullets, the 185gn Berger Long-Range BT and everything in between. Specifying 1-11" twist rate as German suggests additionally allows the 185gn Hybrid to be loaded. It also allows the 210s to be used, but they are seated on the deep side.

Personally, I've used 1-10" twist barrels as others have suggested, not because I needed them particularly, but because that was what was available in a reasonable timescale, and with superb results. The sole penalty is a small theoretical MV reduction as slightly more of the charge's energy goes into spinning the bullet to a higher rpm value over an ideal twist rate. The old argument that too fast twists increase group size no longer appears to apply given the superb quality of match bullets. If you must shoot military FMJBT bullets though, the minimum required twist is still an excellent idea. My next F/TR rifle will use 1-12" though as a 32" Bartlein blank in that rate turned up at a good price and I'm looking forward to seeing what it'll do.

Having moved to a freebore setting that is ideal for the 210gn Berger LRBT, I've found that a 175gn Berger LRBT / H4895 combination that gave 2,806 fps in the previous barrel with around 110 thou' less freebore has lost around 90 fps. However, I'll never know how much of that is due to a different make / example of barrel and how much the freebore. Both tubes have 1-10" twist, so that's a constant.