6br ,1-8 T ,with 75gr Hornady vmax

[Bobbyboy6br]

In the 6BR yes. In the 6X47L it's RE17.

Thank you

 

[fyrewall]

I have just ordered a new 6mm AI, 10 twist barrel. I plan to shoot 87 Vmax bullets.

I modified the Miller Twist Sg approximator (Sg - stability) for Excel use with suggestions from a web post by Miller & Courtney for plastic tip bullets. I can look at the Sg values for multiple bullets on the same page and adjust for twist, tip length, velocity and temperature. That said, practical experience in shooting 87 VMax bullets shows great accuracy from my 8 twist barrels, (sort of like Mr. Cazador's) - .243 Win, 6mm Rem, & 6mm AI. The Sg produced by the 8 twist for 87 Vmax bullets is 3.01 with slight variations for velocity and temperature. If I did not run the Miller business for my 8 twist barrels I would think the 8 twist was just fine because they shoot so well.

Some Miller approximate Sg values:

75 Vmax - 1.63, 12 twist; 2.35, 10 twist; 3.67, 8 twist
87 Vmax - 1.93, 10 twist; 3.01, 8 twist

Thinking about use of 70 & 75 grain bullets in addition to the bullet of choice, the 87 Vmax, I went with a 10 twist.

 

[ben lurkin]

A friend shoots 58 gr v-max in his 8 twist 6 br. Mine is a 12 and actually shoots a little gaster than his, but you ought to see what his does to a Prairie dog! That faster spinning bullet just shreds them.