What twist rate for 120- 123 grain ?

[Grendel-Gene]

I am going to have a custom barrel made and am wondering what twist rate i need to have for optimum performance with 120 - 123 grain grendel ammo? thanks

[bwaites]

Depends on barrel length:

From Bill Alexander:

When we were first working on the Grendel we followed what everyone said about 6.5 calibers and made the barrels with 8 twist rifling. Some barrels would shoot but more often than not the groups were open and the guns were tempremental. One of the very early test rigs had run a 9 twist and it actually shot well despite a less than optimum chamber so out of frustration we ignored conventional wisdom and build some 9 twist units at 24" and 20" barrel lengths. The change in accuracy for the group as a whole was unquestionable. Subsequent production of 9 twist barrels has proven that this is optimum for the caliber.

One of the contributors to the 9 twist is actually the Grendel itself. Pressure limits the ability to slug the bullet to the grooves and the case capacity holds the round to lighter bullets. The 168 grain roundnose nickel steel projectiles are simply not a consideration any more than the 142 and 155 grain SMKs

We have tested barrels as short as 14.5" in 9 twist (not recommended use 1:7.5 this short) with projectiles up to 152 grains and both accuracy and stability are maintained. Equally we have run 9 twist barrels out to 1600 yards (12" group) and the round remains stable and it would appear accurate through the transition velocity. Longer 8 twist barrels often demand velocity reduction for best accuracy

It is our conclusion that the 9 twist offers the best solution for the Grendel for barrels of 20" and longer while the 18" and shorter barrels thrive on 7.5 twist.

[Grendel-Gene]

GREAT!!!! Satern will make custom barrels ( if i read it correctly on their site ) of any caliber and twist rate, so i needed to know exactly what to ask for.... Not sure yet if i will build a 16 inch carbine or a 22 inch "sniper"... (24 is just too long). Thanks

[Drifter]

I've had three Satern barrels with 1:8.75" twist, and each has shot incredibly well with 120-123gr bullets.

Here's a group from the 20":



These two 100-yard 3-shot groups were shot back-to-back with the 18" and 19.5", using either a 123gr Scenar or A-Max handload (can't remember which, but the barrels shoot either equally well):



Here are back-to-back 3-shot groups shot at 100 and 600 yards with the 19.5" (123gr Scenar handload):

[kamrr4437]

My satern is 1:8.75 twist. They do good quality work.