I've owned a bunch of M700 Varmint rifles in .223 and have used bullets from 40 to 55 grains but primarily stick to 40 and 50 grain bullets primarily Hornady V-Max and Nosler BTs.
I've yet to own one that failed to shoot those four bullets into half inch and less groups with no alterations to the rifle other than lower the trigger pull. I've not worked as extenstively with my current rifles as I have some others I had in the past but so far they seem to like most of the same loads.
I use AA2230, AA2460, AA2520, W748, BL-C2, H335 and it seems like I'm leaving something out. I generally work up to book max with all these powders and have gotten down into the .2s and .3s using each of them in various rifles in the past.