7mm 140 grain Barnes ttsx

[Cloudrepair]

I'm trying to decide what cartridge to use with a 7mm 11 twist barrel,
Options 7mm saum, 7mm-08, 7mm-08AI, 280AI.
Will a 140 grain ttsx Barnes stabilize in a 11 twist or do I need to go with 120 ttsx?

 

[mtngun]

With the 140 gr.'s 1.361" length the Miller formula says SF = 1.04 at standard conditions & 2650 fps. A 120 gr. / 1.219" has SF = 1.23. Presumably you'd drive it closer to 3000 fps which would get you up to a respectable 1.3 SF.

 

[Rustystud]

I am using 9:3 or 9:9 twist barrels on my hunting rifles in 7mm. Form 7mm08 to 28 Nosler. Shooting 120- 150 grain Barnes Tipped Triple Shocks.
Nat Lambeth

 

[Cloudrepair]

Thank you all
I have a
pac-nor 7mm 11 twist I'm trying to figure best use for.

 

[Cloudrepair]

With the 140 gr.'s 1.361" length the Miller formula says SF = 1.04 at standard conditions & 2650 fps. A 120 gr. / 1.219" has SF = 1.23. Presumably you'd drive it closer to 3000 fps which would get you up to a respectable 1.3 SF.

Thanks I'll have to look at the Miller formula again to understand/remember what your giving me

 

[RonAKA]

I'm trying to decide what cartridge to use with a 7mm 11 twist barrel,
Options 7mm saum, 7mm-08, 7mm-08AI, 280AI.
Will a 140 grain ttsx Barnes stabilize in a 11 twist or do I need to go with 120 ttsx?

Using the Berger Calculator, I get a stability of 1.08 with velocity of 2950, and 1.11 with 3150 fps. Stability is relatively insensitive to velocity, so I would suggest this bullet is not suitable for your 11 twist, although it is just barely stable, and might work at higher elevations.

The Berger 150 grain Classic Hunter should be fine though at 1.5, and the 140 VLD Hunter, and 168 grain Classic OK at about 1.3. Some degradation of BC, but stable.

 

[Cloudrepair]

Using the Berger Calculator, I get a stability of 1.08 with velocity of 2950, and 1.11 with 3150 fps. Stability is relatively insensitive to velocity, so I would suggest this bullet is not suitable for your 11 twist, although it is just barely stable, and might work at higher elevations.

The Berger 150 grain Classic Hunter should be fine though at 1.5, and the 140 VLD Hunter, and 168 grain Classic OK at about 1.3. Some degradation of BC, but stable.

Thanks