6.5 twist rate

[Larryh128]

Since there are so many 6.5 users here, my question is what is going to be the optimum twist rate for 120-130 gr hunting bullets? I have absolutely NO interest in swinging 140's although I know the BC is higher etc.

 

[KevinThomas]

You should get by with a 1x9" here easily, and may even be able to go a bit slower than this. Just make sure you never want to use the 139s, 140s or 142s, since this is a one-way trip. Personally, I recommend the faster twist that will always leave you with the option, and yet won't be a problem with the 120-130 grain offerings you've mentioned here.

 

[bowslngr]

You should get by with a 1x9" here easily, and may even be able to go a bit slower than this. Just make sure you never want to use the 139s, 140s or 142s, since this is a one-way trip. Personally, I recommend the faster twist that will always leave you with the option, and yet won't be a problem with the 120-130 grain offerings you've mentioned here.

I agree. Go with at least 1:8.5 and you are pretty close to unlimited.

 

[RonAKA]

It is highly dependent on the type of bullet you shoot. I have a .264WM with a 10 twist. Nosler 140 Partitions, and Sierra 140 Boat Tails go unstable in cold weather, and are only marginal in warmer. 1 in 9 seems ok with both those bullets as I have another gun in that twist.

But say you want to shoot the Berger 130 grain VLD hunting then you need a 1 in 8 according to Berger.

http://www.bergerbullets.com/Products/All%20Bullets.html

For a target gun you want to go a slow as possible. But, for hunting I would go faster to be sure you can hunt. So 1 in 9 if you want to shoot 130 grain regular boat tails or flat base, but 1 in 8 if you have interest in shooting the Berger 130 VLD's. You just may get away with the VLD's at 9 twist, but then again you may not.

 

[jbarnwell]

I shoot a 8.5 twist Krieger on a 6.5/06 AI. Have no problem with all of the hunting 140/139's and shoots the 120 Ballistic Tips and 125 Partitions very well. All of these will shoot .5 MOA and better. This is a hunting rifle with a #5 contour barrel.

 

[HTSmith]

I do not see the disadvantage of going with an 8" twist and being able to shoot any bullet you want. My 8" twist shoots its very tightest groups with 100 Gr bullets. A 9" will probably handle 130's fine, but you eventually you'll want to try some of those slick 140 Gr and you'll be out of luck. Why limit yourself? Just my $.02

 

[Bnhpr]

I do not see the disadvantage of going with an 8" twist and being able to shoot any bullet you want. My 8" twist shoots its very tightest groups with 100 Gr bullets. A 9" will probably handle 130's fine, but you eventually you'll want to try some of those slick 140 Gr and you'll be out of luck. Why limit yourself? Just my $.02

+1

The 140 vld and 142 smk shoot so well..

 

[louielouie]

You could always use this calculator http://www.jbmballistics.com/cgi-bin/jbmstab-5.1.cgi to see what an 'optimum' twist rate is. I ran it against the 140gr Nosler CustComp (1.315 in.) and a 8.5" twist running 2500 fps was stable down to freezing with a low barometric pressure (high altitude). I don't know if there are any velocity advantages by reducing the twist rate ~12% (8 -> 9).

 

[dmg264]

I have had a few 8.5 twist barrels and all of them have shot berger 140's very well. I had one 9 twist and it shot everything up to 130 well. All the barrels were chambered in 6.5-284.

 

[boltman13]

My Hart 6.5 barrel with a 1:8 twist shoots 139-142"s very well but the single best groups I have had so far were with 120 gr A-maxes. Go figure.