Re: VARGET POWDER
According to the Sierra manual, the max load listed is 43 grains for a 60 grain (3700.) 41.1 for a 75 (3500) and the 34.6 for a 90 (3000) and 34.2 for a 100 grain (2900.) These sound like low charges, but be aware that a 243 has a much different burn rate than a 308 even though it is the same case. these are MAX loads, make sure you start much lower than that and use a chrony. I hope that helps.
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.