Ive been reloading diferent loads w different powders(due to availability!). I have good results w certain recipes at 25 and 100 yds. Then if they are good performers I go out to 200 yds., Then to 300 yds. w/ 5-10 shots. Im having weird results at my 300 yds on more than one load. Shots are going erratic 12" scattered and dropping from 6-10". I run a wire brush through barrel after 5-10 shots and let the barrel cool down after 2-3 shots once its hot to touch. I try to keep things consistent. I weigh ea load seperately into indentically trimmed cases. I back off the case neck 1/2 turn from touching. My groupings are within a 3" circle at 100 and within 5" at 200yds. Im getting chrono speeds of 2850-3200 fps. Using Accubonds and Hornady sst boat tails w/ H4831sc, RL25, H1000, Retumbo and Magnum. Just cant figure why my loads are falling away at 300yds.