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6mm twist rate

javy

Sergeant
Full Member
Minuteman
Feb 22, 2011
270
32
67
Texas
Would a 8 twist be to fast for 85gr hunting bullets? From a 243.
Thanks
 
It is faster than needed but otherwise should be fine. Any accuracy loss would likely only be detectable in short range benchrest.
 
Would a 8 twist be to fast for 85gr hunting bullets? From a 243.
Thanks

It might be, depending on which exact bullet.

I used to have a 260 Remington with a 1-8 barrel that would blow up Hornady 95 Vmax like little grenades.
 
use this, i use it even for non-berger bullets. It will tell you if your bullet will be stable.

 
use this, i use it even for non-berger bullets. It will tell you if your bullet will be stable.

The question is not whether it will be stable. It will be. The question is whether it will be too fast, specifically, will it blow up the bullets by spinning them too fast, and whether it will be less accurate because spinning faster exaggerates any asymmetry in the bullets.
 
The question is not whether it will be stable. It will be. The question is whether it will be too fast, specifically, will it blow up the bullets by spinning them too fast, and whether it will be less accurate because spinning faster exaggerates any asymmetry in the bullets.

I agree, but this site it will tell you if it is stable, if it is stable it will be within the range the calculator will estimate/show you. If it is out of range it will not work either way.

Before responding I actually went to put a 85gr bullet, just to see it was even stable with that twist...it came up marginally stable requiring a 1:7.75 at minimum. That said...the calculator showed me it was marginal. It may help if the OP can actually explain exact specs of the bullet to provide a better answer on either case. Like starting BC, Length, estimated speed, etc

Id start with stability first before assuming it will blow up because its spinning too fast. I guess that I should have been more clear in my response.
 
MVx720/spin rate = RPM

Anything over 300k rpm is in the danger zone. It CAN still work. It is just straddling the line of staying together vs. having bullet failures.

I have run Speer 85 spitzers at 3500 fps out of an 8 twist in a 243 Ackley. I didn't notice any bullet failures, but only shot that load for around 100 rounds on a brand new barrel. I have had bullet failures with 7 twist 223 running 68 and 75 grain bullets and 7.5 twist barrels in 243 Ackley. In both cases the bullets were spinning over 300k rpm.
 
Thanks for your input.
I have decided to run a 7.5 twist with the Berger 108 elite hunter as this is more a hunting rifle than a match type rifle.
Now need to get free bore right.

thanks all