I have been shooting the 300 Wby for over 30 years and like it. It kicks and the best ammo is to go with the Rem 300 Wby. The brass is very good and cheaper than the Wby. Wby ammo is $60.00 and up and some C&C 338 Win ammo is cheaper and easier to find than 300 Wby. The 338 is a nice case to load for, several of my 340 Wby loads are at 338 velocity. The 338 will work great on bear but it may be too much for your son. Good luck! Randy
The Remington 300 Wby ammo is the worst stuff I have ever used and the brass is horrible compared to Wby brass. The Remington ammo is a full 100 fps slower than the proper ammo too! Go with the good stuff, either Wby or Norma ammo. There may well be other "good stuff" but I haven't bought any factory Wby ammo in a while. Had a client give me a box a year or so ago and it was good stuff; Hornady loaded factory ammo with Norma made brass.
The 200 grain loads, to me, are noticeably harder recoiling. I have killed more than 10 bull elk with 165 grain bullets; all at less than 100 yards however. I killed a few with 200 grain soft points and a couple of 180 grain soft points. I even shot one with an Barnes original softpoint (250 grain) roundnose. Shot quite a few of the Barnes softpoints back in the 80s. Accuracy was not great but performance at the killing end was! Back when I only timber hunted, 100 yards was a long shot!
