An a 308 win will do every thing better , much better with no down side IMO .
I'm considering getting one of the x39's with the mannlcher stock too Fyredup, so they do shoot pretty decent ? 100m-150m is about a good max range for the x39 IMO and much more you loose allot of your power after that anyways. As long as they'll hold 1moa that would be just fine,
IMO thats a option if your stuck with only a rifle in that calibre but everything you going to do to improve the x39 will work better in 308 win or 300 savage or 30-06 an all can be loaded to lower levels . I would never purposly buy a a marginal poweer rifle for deer intentioaly it makes no sence.
. Especially if you reload them with some decent projectiles like A-max or a good SP/BT Serria, I'd think they should be pretty good for deer, ect.