Re: muzzle velocity veriation
too many problems with that question.
1, how accurate is your chrono?
2, how accurate are you with your powder charges?
3, how much vibrations are in your barrel?
We can keep on with this for many many replys. so you need to ask yourself some questions If your reloads are giving you good accuracy and your chrono says that you have a huge extreme spread why worry.
My favorite hunting load (according to my friends chrono), has es of 80+/- fps and I still have 5 shot groups under 1 inch @ 100 meters. My fav target load (using the same chono), has -25 fps es but, the accuracy remains the same (under 1 inch @100 meters).
The only difference is target loads / less powder (different powder also), less speed std primer = less recoil and velosity but, the accuracy remains the same
Hunting loads / more powder, mag primer, lots more vel and lots more recoil but same accuracy.
So, I believe that the accuracy to es problem that I have is in my head and not with my rifle