Re: 300 RUM question
I agree with the comments made about "any excuse to buy a new gun"! That may be what you need to do......
However, from your post I would say you have far from exhausted your bullet / powder options. If you like the rifle (other than it not shooting well), you might try several more bullet and powder combinations before you declare it DOA. It looks like you have only tried ballistic tip type bullets. Try some SMKs, maybe some barnes TSX in the heavier weights. Also take a hard look at your scope base, rings and maybe the scope itself. Maybe your barrel would bennefit from being floated, stock bedded?? How quickly are you shooting your groups? Those light factory barrels can heat up and move on you.........
Yes, you may need to ditch this rifle, but just from your initial post, I am not sure you have gone through all the steps to declare this one a dud yet.