308 twist rate.

[Caleb85]

would a 10 twist work for a 308 win useing 155gr to 175gr?

 

[284winner]

Easily

 

[memilanuk]

Yep

 

[Caleb85]

Thank you!!

 

[Caleb85]

What's the lightest and heavyset it will take?

 

[Sniper338]

I say no. I have a 10 twist and it wants 175 all day long.

155s would shoot worth a flip!! If i went with 155s id do a 11.5 or 12 twist

 

[Ned Ludd]

I've shot many hundreds of 150s and 155s from a 10-twist barrel with excellent results. A 10-twist barrel should work for almost any light 308 bullet you might use, certainly down to 150 gr, which I have shot from one many times. It will be overspinning the lighter pills, but this really isn't a problem in terms of precision in most circumstances. It's the upper end of bullet weight (length) where twist rate can become limiting. Underspinning bullets will at a minimum mean you effectively "lose" some BC, meaning you're giving up some performance, and in a worse case scenario may mean instability (i.e. tumbling and key holing at the target. A 10-twist barrel should typically be able to handle most bullets in up to about 200-210 gr, but may start to be an issue when you get to the 215-230 gr range.

 

[Caleb85]

Well I said 155 just to cover it but it will probably be more 168 to 175

 

[Ned Ludd]

Caleb, unless you're planning on jumping up to 215-230 gr bullets, which not all that many people do in a .308, you're absolutely GTG with the 10-twist. It will stabilize a very wide range of bullet weights (lengths) and is a very good choice if you don't know exactly which bullet(s) you might end up wanting to shoot.

 

[memilanuk]

10 twist has been the standard in most factory .30 cal guns for decades, for good reason. It will handle about anything you care to throw down it, as Grant already mentioned. When we first started shooting the 12 F/TRs in matches, one of our team members opted for a 10 twist instead of the default 12 twist. There was no discernible difference between his scores and any of the rest of ours. The only problem I was ever aware of involved a warm load of N540, hot temps (early/mid September in Raton, NM) and velocities that got too high (back-calculated from drops to somewhere north of 3200 fps with 155 VLDs), resulting in a couple bullets not making it to the target

Otherwise... I have a little shorty 20" 10 PC-SR that just *loves* S2156MKs @ ~2830fps. Unfortunately when the local PRS matches do have ".308 only" side events, they typically require 168-178gn bullet weights so as to be 'tacticool' :/

Further proof of the viability of 155s from a 10 twist can be seen here:

http://www.6mmbr.com/gunweek059.html

 

[Shynloco]

I say no. I have a 10 twist and it wants 175 all day long.

155s would shoot worth a flip!! If i went with 155s id do a 11.5 or 12 twist

I experienced much the same. The 168's and 175's put together very accurate and consistent groups. The 155's not so much.

Alex

 

[Steve Blair]

would a 10 twist work for a 308 win useing 155gr to 175gr?

My 26" .308 w/10" twist shoots Berger 155.5 Fullbores unreasonably well. I've won F-TR matches and cleaned MR targets with it. High quality bullets are not usually disturbed by spinning a little fast. My old .30-'06 10" twist shot Sierra 125 Spitzers very well, too.

 

[284winner]

208 Amax will be great too. My 10 twist loves 185 Berger's best. It shoots 155s pretty good too out to 300 yards. 168s about the best to 600. Berger 185s excellent to 1000.

 

[Caleb85]

What would one recommend for groove? 5R? 4 groove? 6 groove?

 

[Autoverminator]

10 twist rock 5r @ 26" for my 308 ftr. Excellent results with the 185gr hybrids at 600y and 1000y.

Buy with confidence.

 

[Steve Blair]

What would one recommend for groove? 5R? 4 groove? 6 groove?

I've seen excellent accuracy in barrels from two to sixteen grooves in a variety of land/groove types, including polygonal. This is less important than barrel quality.

 

[M14AMU]

http://forum.accurateshooter.com/threads/i-may-have-missed-the-boat.3907858/#post-36819202

 

[Liven The Dream]

I will jump in on the 5R part ????
There is only one thru 5R it is the Boots Obermeyer one ......... Jack Krieger can make you one now by license from Obermeyer.
The other 5R's are different by default do to Patent Right.
Boots 5R barrels that hammer the X Ring are 1-11.5 twist. He makes 10' and others. Those 11.5 where the M-14 barrel of choice in the day.
I had a couple on Bolt Guns that never found a bullet the did not like ? ( maybe 180 MK new style )

I shoot a lot of 155's now do being a Palma shooter. We have fellow in the PNW that makes barrels , he is making 1-12 left Twist .
They are doing a great job with all the newer 155's .
WE are running 30 and 32 in. long barrels this but our 155's at 3020 to 3050 at the muzzle.

You can find a Famous Long Range Shooter on the Forum that did Run 10 Twist Barrels on his Palma Rifles !
I think he just Won the Nationals at Perry?

Good Shooting,
Don

 

[Steve Blair]

I will jump in on the 5R part ????
There is only one thru 5R it is the Boots Obermeyer one ......... Jack Krieger can make you one now by license from Obermeyer.
The other 5R's are different by default do to Patent Right.

There is no issued patent for 5R rifling. Even if there had been, patent durations are 17 or 20 years, depending upon filing date. Any patent issued would be long expired and now public domain. Also, the term "5R" has no issued copyright and may therefore be used freely. Thus, barrels may be made that are identical to Obermeyer barrels (at least in form, if not quality) and sold as "5R".

This does not detract from Boots' excellent barrels or his long history of innovation.

 

[Liven The Dream]

There is no issued patent for 5R rifling. Even if there had been, patent durations are 17 or 20 years, depending upon filing date. Any patent issued would be long expired and now public domain. Also, the term "5R" has no issued copyright and may therefore be used freely. Thus, barrels may be made that are identical to Obermeyer barrels (at least in form, if not quality) and sold as "5R".

This does not detract from Boots' excellent barrels or his long history of innovation.

Will then I have been filled with BS all these years . I would say we are never to old to learn.
Thanks for your input.