Good thing I have a 1-7 barrel.
I've mostly settled on the 140gr BD-2 in my 277 so far and it kills fine if it's placed right. Just not quickly if it's lungs only. Same as every other copper bullet I've used. I'd use the 150, but due to magazine length restriction, the 150 ends up eating enough powder space to actually step backwards despite the higher BC until you're well past ranges I shoot at. Anything over 1.60" in length and it's eating too much powder for my magazine.
I've got the 152gr DRT loaded for my next hunt with it, really curious to see how they do on game. Big departure from all the other non-lead bullets.
I've shot the LRX, TTSX, Cutting edge razor, Leigh controlled chaos, hammer hunter and absolute in 30, 27 and 26cal. Everything died, just always looking for that slightly better.