115-grain TSX is designed to stabilize in a 10 twist.
Barnes claims a 1-in-9" twist is required.
![[Linked Image]](https://www.24hourcampfire.com/ubbthreads/gallery/80/full/138674.jpg)
I have discussed this before. When bullet makers list a particular twist on their website, or a box of bullets, it's because they're afraid somewhere, sometime a customer will shoot in "conditions" where a bullet might not stabilize--say when hunting below zero along the shoreline of the Arctic Ocean for caribou. It does not mean that a slower twist won't work fine for all other conditions.
A good example is the .270-caliber 170-grain Berger EOL Elite Hunter. It has shot very accurately in two different 1:10 twist .270 Winchesters here where I live in Montana--and the two ranges I use are on the valley floor, 4000 feet above sea level--where its stability rating according to the Berger program is over 1.3, quite a way above the 1.0 minimum. It would be even more stable when hunting at elevations up to 9000 feet in the mountains above the valley--and according to Berger's own stability problem is "marginally stable" even in standard conditions of 59 Fahrenheit at sea level.
Yet Berger suggests a 1:8 twist. This is NOT just to stabilize the bullet, but to maximize ballistic coeffcient--which tops out at a 1.5 rating. With the 170-grain .270 bullet, shooting it at 2750 fps at 4000 feet reduces the bullet's "maximum" G7 BC of .339 to .323. Big deal.
