Hunter,
If he has no problems shooting you 300 then buy him a 300 Winchester,or 300 WSM.They make quality ammo for both heavy and medium game like the 165 Nosler.There are plenty of guns that will fill the void,7mm Rem Mag,7MM WSM,300 Win,300 WSM,300 Weatherby,270 Weatherby,270 WSM and so on.

I have no qualms about shooting deer and antelope with my .338 win mag,I acually like it.It's not needed but hey it works.
BBJ