Since he's 14 and currently uses a 20 gauge with no problems, all of the mentioned cartridges will be fine for deer and antelope. As for the Savage Axis, I have a couple friends that own them, 1 in youth 243, 1 in 30'06. Both are plenty accurate (1-1.5 moa with factory ammo), both have heavy triggers. I'd avoid combo packages as the scopes are normally brandless chinese junk.