Buckskin: Welcome to the forum, and as yer favorite Custom Rifle forum moderator I would be loath to suggest anything less than whatever you would like to do to further customize your rum but, and this is a fairly large one, you have already taken several animals at 300 yds and a goat in a speedo at 448 - what am I missing?
When you say 'countless numbers of load configurations' - how many rounds are we talking about here? Is your barrel shot out (not with 300 and 450 yd shots it isn't)? Coppered up maybe but geez, a 450 yd shot is pretty dang good even if it was.
I would be tempted to suggest - naw, I will suggest that before you drop lots of $ on new stuff that will have to go through a break-in period, like a new barrel, you consider bore lapping or fire lapping your barrel to see if that improves your groups on paper. Drop on down to Veral Smiths forum and read what he has to say about bore lapping and if you like what you read then get a bore lapping kit from him, lap that barrel and then see how she shoots. You may get a inexpensive fix to your concerns. Hope this helps.