I experienced the sameLong story/journey short version.
Was given a Rem700 300wm stainless with the grey laminated stock. Tried every quality factory ammo for 2 years, my shot gun gave tighter groups! Sat in the safe a few years then a friend taught me how to reload. 7828 with Berger 210's and got consistent 1" to 1.5", then tried Berger's 215's, AND done!!!
I built a 300WM with the intention of shooting 190gr ABLR's.
It wouldn't shoot them. I also couldn't get acceptable accuracy from 200 or 212gr ELD-X's. I tried a few other bullets and some factory ammo. Nothing shot under 1.5 moa
It was suggested I try the 215's and the rest was history. Average group size is .449"