Nice find. Don't blame you for not wanting to sell that jewel. That'll make a nice one for the collection.
I've never had the pleasure of shooting any of the 300's. One day, maybe.
Had a friend went out to Montana to hunt Elk and or Moose with an old air force friend of his. Friends, friend had some lighter weight gun in 300 win mag. that he used as a backup against bear. My friend shot it a few times and said it was ugly punishing. His friend said he never shoots it, he just lets his friends try it out and in the process he can make sure it's still zero'd just in case he has to use it. hahaha