When a rifle has a faster twist for example 1:10 as aposed to 1:11.25 it can stabalize heavier bullets. the bullet Will spin once in the barrel every 10 inches of barrel length with a 1:10 twist and 1 time in 12 inches for every 12 inches of barrel. 1:11.25 twist is good for your 175 smk or 178 amax or bthp hornadys. If you want to be shooting the bullets in the 200+gr range then the 1:10 would be the best.