Stick with a 9 twist. 140's are for velocity freaks!
Heavy = Accurate.
The 3500 & 3600 fps looks great on paper but won't look good on paper! (Targets that is!)
Try the 176 cauterucio, you will love it.
Do a search on that bullet, it has a .750 BC.
I dont know if I'd use it on elk, but deer or smaller heck yea!
Good Luck!