The 30-06 is boring. Boringly accurate and, boringly effective. I can't see where your son would be making a mistake with a good bolt action 30-06.
I have taken a pickup truck of deer with the '06, almost invariably with a 150 grain Hornady over 52 grs. of IMR 4064. Three 3 moose have succumbed handily to the '06.The first to a 168 Barnes TSX and the last two with 180 Nosler Partitions. I spent a summer, prior to my first Newfoundland moose hunt shooting an '06, a 7 mm Rem. Mag and a .375. I know, the 7MM Rem shoot a bit flatter and the 375 hits harder, but at the distances I would ever have to shoot, from a practical matter, there wasn't a dime's worth of difference. Lesson learned....the 06 was easier to shoot from field positions.
Three shots and three moose from 150 to 250 yards. The first rifle was a Rem. 700 with the Barnes 168 grain , the second was with a Tikka T3 and the last was with a Ruger No1S. The latter two both with heavy doses of H4350 and 180 Noslers. All three of those rifles would shoot 5 shots into 1 inch groups. I am sure that other cartridges would have done petty the same.
I type this looking at three gun cabinets holding at least 50 guns. Cartridges run from .22 LR through .222's and .223's through a few 6mms's, some 7mm's, a bunch of 30's, a 375's, a couple 45-70's and a .458. The .35's and the 348's are long gone.
There isn't anything about the '06 that members here don't know. Whelen got it right when he wrote, " The 30-06 is never a mistake." After more than 50 years hand loading and knocking stuff off, I think Whelan got it right.
O, I need to add, that maybe,although I am battling the actuarial tables here, a 6.5 of some sort is probably is in the not too distant future.
To the original post, 30-06 for sure in whatever bolt action rifle your son likes.
