Re: Brass Weight?
Most BR shooters use cases within 2 grains of each other. This is of course more or less than neccasary depending on how big the case is. A 308 Win case 2 grains more than its comparision case will be more noticable than a .300 Win mag. (grain differance per total weight ratio.) The 2 grains in a 308 wont amount to much unless you are trying to shoot a .000" group. I think if it werent for shooting the impossible, none of us would be here on this site. For best results, shoot the same brass.
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.