I have two in .300 Sav., an EG and a T, and I have an F in .358 Win.that used to be a .308. Yes, have JES bore it to .358 Win, or .338 Fed and you'll have a nice big bore to compliment your .300.
Reloading for any of the 99s isn't any kind of a problem that I've experienced, but I can also...