For factory ammo, I prefer the Winchester Supreme 180gr Accubonds or the Elite XP3's. I reload my 300WM since 2005 with the 180gr AB's, but have used the factory previously and my hunting buddies that shoot 300WM with factory loads prefer the 2 listed.
Reloads with RL22 with 215 primers works great for me!
Have fun on the elk hunt with your dad !!
The XP3 would also be my first choice in a factory load for elk. If those didn't shoot, federal trophy bonded tips would be next. Any good bullets should be just fine, including TTSX, TSX, Partition, Accubond, Scirocco, Gmx, etc. I'd shoot whichever good bullets was most accurate out of your rifle.
