Best twist rate for a bolt action Grendel

[tango29]

Hoard,

What is the best twist rate for a 6.5 Grebdel bolt action rifle. Working on a savage 10 FCM conversion to grendel and would like to know the best twist rate for the new barrel.

[JASmith]

Excellent project!

Absent contrary advice, the twist rates needed to stabilize bullets are pretty much the same whether bolt or gas guns. I am using a TC Encore with a 9-twist 18" barrel but have not yet tested bullets heavier than 130 grains. I expect to test heavier bullets in the near future.

Some prefer an 8-twist to be sure of stabilizing the longest bullets, especially when the barrel is less than 19 or 20 inches long.

With the swelling of lead-free bullet advocacy, there may be some advantage to going with the 8-twist if you want to use 140 gr-class bullets.

[KentuckyBuddha]

Also, there may not be the penalty one might think with lighter pills. I got 1/9" twist in 20" for a bolt project, and I wish I had gone with 1/8". The fact is for far and away the most part I will probably be shooting 123 grain projectiles for the most part and for those it won't make one bit of difference at all between the two.

[bwaites]

I would not go higher than a 8-twist, and considering all the long monometals and possibly heavy hunting bullets usable in a bolt gun, I might even consider a 7.5. The more I read on the subject, the more I believe that spinning a bullet faster is never a bad thing.

[KentuckyBuddha]

If you wanted to throw around those Lapua Naturalis bullets for hunting (and why wouldn't you)...having 1/7.5" sounds like a very good idea.

[FW Conch]

I finished a Savage build in October, and I went with an 8 twist. Haven't been able to shoot it a lot, but my best load to this point is 120grn Nos BT over 8208XBR. My best 5 shot group so far is .640" off the hood of my truck. I hope to shoot the heaviest bullets that will group well, which means the longest bullets, so it is at least 8 twist for me.

Good Luck ... Please let us know what you go with :-))

[Joseph5]

Todd Hodnet who does a lot of training of military snipers and also rifle/load/ammunition testing and development for the military wrote an article discussing twist rates and bullet stability. One barrel he mentioned testing was either a 1 in 4 or 1 in 6 twist 308 chambered barrel. He stated that he found lots of advantages to shooting a faster than traditional twist and no downsides.

[Drift]

My 18" 1 in 8.5 twist barrel has no problems with the 140gr bullets. I have no opinion on heavier bullets.