Twist rates for shorter and longer barrels...

[Grendel-Gene]

I know this has been discussed before but i dont know where the thread is anymore....

I understand that the ideal twist rate varies with the barrel length; The 18" Saterns are 1:8 I believe....So, What is the ideal twist for a 20"?

I ask because i ordered a 20 inch Shilen just now and its 1:9, so i am wanting to know if that is in the proper twist range for that length barrel.

Thanks

Gene

[Drifter]

I've shot 18" to 20" Saterns with 1:8.75" twist that performed very well with bullets suited to the Grendel. My guess is that a Shilen 1:9" will be just fine.

[Grendel-Gene]

Good to know for sure! thanks!

[Bwild97]

I'm pushing 142g pills out of my 24" 1:9 twist with out issue.

[VASCAR2]

Bill A answered my question about twist rate because it didn't seem to be the same with 5.56 (longer heavier bullets faster twist ie 77 grain 1:7,lighter 45 grain 1:12 twist). Bill advised their testing showed the faster twist improved accuracy on the shorter barrels especially 14.5" and shorter. From what I've read 1:9 twist was used for decades with other 6.5 cartridges.

I have a 1:9 twist Shaw 16" barrel and a 20" Shilen 1:9. I haven't shot any bullets heavier 123 grains but so far I have been impressed with cartridge accuracy with a wide variety bullet weights, powders.