12" 6.5G Barrel Twist Rate?

[ibshane]

Should a 12" barrel have the traditional 1:8" twist?

I see some of the shorter barrels out there have a 1:7.5" twist.

When I do get a 12" barrel, I plan to still shoot 120-123 gr. pills.

[BluntForceTrauma]

Using Berger Bullet's twist rate stability calculator

[KentuckyBuddha]

Wouldn't a 1/7 twist be better if one were say at 1000ft (304m) at 0F (-18C) even with 123gr?

[kmon]

The 130gr Hybrid BFT used in his example is longer than the 123gr offerings that I know of and would require more twist to stabilize. Gaining altitude and/or temperature will increase stability of the bullet. The example he gave above gives a SG=1.50 give it 100 degrees and 6000 feet elevation and SG=1.81. At 0 degrees and 1000 feet elevation SG=1.56

Any SG 1.5 or over is considered stable and you are not loosing BC due to instability.

Here is the link for the Berger twistrate calculator, you can choose one of their bullets or enter your own data for the bullet you use or plan to use.

http://bergerbullets.com/twist-rate-calculator/

[BluntForceTrauma]

[ibshane]

Thanks!