Working up a load - Barnes Bullets 30353 TSX 30 Caliber .308 180 GR TSX Boat Tail 50 Box

I’m working up a new Elk load for my 20 yr old 300 win. mag. I noted an immediate reduction in group size with this bullet, with first 5 shot groups 1 3/4” at 200 yds. Still trying additional powder charges while working my way to maximum load (which my rifle has always preferred). I hunted with this gun for over 20 yrs, moose, bear and deer and am pleased to discover what it can do, never before done much better than an occasional 2” 200 yd. group. CCI mag large rifle primers, RL22 powder and Barnes 30353 bullets.