I have a 300 RUM M700 Sendero I have been having issues with. I have had 4 different bullets with loads that would give me at least .5 moa 3 shot groups. 208 AMAX, 94 gr Retumo 225 gr hornady, 87 gr Retumbo 200 gr Accubond, 93.5 gr Retumbo 180 gr TTSX, 95 gr Retumbo Each load would shoot well, and then for no apparent reason, it would not group any more. I would start load development again. It was originally unbraked and the Amaxs worked well. After finally deciding to quit punishing myself, I had a break installed ( Holland QD) by a local gunsmith. It now has become erratic. One day it will give me a stellar group, then the next, the very same load will open up to 4+ moa. I skim bedded it to see if it would improve accuracy, but it is still giving me inconsistent groups. It would throw down a 1.25" group @ 300yds consistently, and then the next day with the same exact load, gives me 8+ inch groups. Same conditions, same set up. The crown on it is very rough where the gunsmith milled it, but looks good by the rifling. It has approximately 250 rounds through it. I torqued the action, even over torqued when it goes erratic to see if it cures it. No dice. I was going to use it on a elk hunt this weekend, but don't feel confident with it after all this. I don't want to go under gunned, but I'll be taking my tried and true 308 that will always give me .5 MOA. I regress. Would it be burned out? The scope is a MK4 4.5-14. Is the scope the issue? I'll swap out with a night force when I get back from my elk hunt, to see if it's the issue. I'm thinking of taking it to G A Precision since Kirby is a few states away, to see if they find anything out of the ordinary. I would take the 338 lapua I just received from kirby allen a couple months ago on the elk hunt, but I have more invested in it than the airlines would cover if it got "lost". By the way, it's shooting well under .5 moa, but thats another story. Thanks for any help.