I’ve got an introductory year (2001) 300 WSM that I thought about mounting in a new stock because it had a 12-7/8” LoP. So, I did a lot of shopping. In addition to Manners and McMillan, gunpartscorp.com usually has Hogue and some good factory walnut stocks.
In the end, I made a mesquite butt-spacer that I’m very happy with. The factory FW stock looks like its new but the pistol grip is not great for torque-mitigation. So, I learned to cradle the butt in my left hand to control torque.