10 works for the 165 (most of the time) 9 will do both 165 & 175, and will most likely work with the 170 Bergers.
or be 100% safe & get an 8.5t
most bbl manufactures will do all.
Originally Posted by 450matt
I am looking to have my model 70 rebarrled. Its chambered in 270 weatherby and I want to stay with that. I am wanting to be able to shoot the matrix 165 and 175bbullets. I was wondering what twist would be needed for these bullets? And who makes fast twist barrels for 270's? And also just wanted thought on how the gun might performe with these bullets? The gun would only be used for play and maybe deer.