If you want smokeless, get the Savage, bed the sucker or go all the way and install the 3rd pillar, and you'll have the best long range factory ML out there.
If you want to stick with BP and BP subs, I recommend the Omega because it is easy to bed and accurize -- not so the break actions.
My Omega has had pillars added and is bedded, and will shoot .75-1.00" at 100 yds for the majority of groups as long as I let the barrel cool. It holds similar accuracy out to 400 yds consistently.
I made one run with it to 500 yds with the 325gr Hornady FTX .458" and it was pretty good, 8" group with most of the spread being wind.
IMHO the best two long range bullets out there right now are the 200gr Shockwave (NOT the 250) and the 325gr FTX with the 265gr FTX coming in a close to that. I knock the 250gr Shockwave because a) it is ballistically inferior to both the 200 and 300 at long range, and b) I know the 200 performs well on game across a wide range of velocities (I've killed deer to 338 yds with it) and the 250 is a bit frangile. I have not shot any animals with the 325gr FTX yet but will this fall.