I am going to start on a 308 build, I wanted to get some feedback from you guys about length and twist of the barrel. I want to reach 1K yards with it. I know that type of bullet and grain is a variable, but I want to get the right length of barrel. I've read that you need at least 20" to even get close. But velocity is an issue with that short of a barrel. I was thinking of going either 22",24" or 26", just not sure which yet.