Due to state restrictions all of my resident deer hunting is done with a ML. I have a T/C Omega which I accurized (pillars/bedding). Until this past year I shot 110gr 777 and a 200gr Shockwave (optimal accuracy) at 2050 fps and have taken 3 deer past 300 yds with a long shot of 338 yds. I regularly target shoot this load to 400 yds but 350 yds on deer is about where I'd limit it, just too slow past that.
This past year the FTX bullets were released so I switched to the .458 325gr FTX and a max load of 135gr 777 at 1950 fps. This load virtually duplicates the trajectory of my previous load to 300 yds then beats it after that, with twice the energy and half the wind drift. I have shot this load to 500 yds with good results but my only kills with it so far were a deer at under 20 yds (BRUTAL on it) and a coyote at 140 yds.
I am currently modifying a Savage Model 11 package gun I bought into a switch-barrel gun so I have a 243Win barrel for coyotes and a Pac-Nor .45cal smokeless ML barrel. People are pushing the 200 Shockwave to nearly 3000 fps with this setup, with 2700-2900 fps being easily acheivable. This would push the max range on game (extrapolating from my previous experience) to around 600 yds. I will also try the 275gr Parker Extreme .45cal bullet sabotless at 2400-2600 fps, which will not be quite as flat but will get another 100 yds or so due to increased energy delivery.
The real difference is that none of these bullets fare very well in the wind. Drift compensations compared to drop values get a bit ridiculous compared to shooting CF rifles. Therefore conditions really become a limiting factor, for all of my 300+ yd shots it was virtually dead calm.
500yd group with the ftx. It was a rotten 100F day and windy so I was happy with this group.
The accurized omega.
The smokeless ML.