Here's the data from a Savage 308 of my fathers. 24" 10 twist. Super accurate load also. 2.80 COAL. Lapua brass and CCI LRPWhat velocity do you get with your 45 grain load and those 178s? I used to have a marlin bolt gun that really liked the 178 and 168s but I sold it to a buddy that wanted to get into hunting. I believe it was a 1/11 twist or 1/12. I currently have a howa that is a 1/10 twist.