Just bought a little used 4566 in it's box w/all paperwork and spent shell case ect. I've loaded several powder weights w/Tightgroup and Win. 231 with a FMJ 230 gr. ball type bullet, and it shoots low all the time. Now, it could be me, but in case it's not, what would you 3rd gen. guys reccommend as a starting point for my reloads? Lighter bullet? Powder change? Any help is appreciated. My old 4506 didn't do this.