Re: Barrel rate of twist
Fortunately, the 12x works very well with 185-200 grain bullets. 215 no but up to 200 yes. And as GS pointed out, only in regards to jacketed lead and not solid copper.
Long range shooting is a process that ends with a result. Once you start to focus on the result (how bad your last shot was, how big the group is going to be, what your buck will score, what your match score is, what place you are in...) then you loose the capacity to focus on the process.