i have a model 70 win. in 300wsm that I'm trying to turn into a tack driver from 400-800 yards. right now I'm pulling deer down hard out to 350 yards 9 out of 10 shots. I just picked up a AR 7.62 as a close in gun and like the 300wsm and want to push it as out as far i can. id like to use if for pronghorn, deer and yotes out west. also looking to put a heavier barrel on it any thoughts on twist? i typically shoot 165 or 168 grains.