I shoot contenders exclusively.
I've got a 15" barrel in 45-70.
I've got a 16" 444 Marlin barrel.
I wouldn't alter either.
That 15" .44 magnum will serve you well once you shoot it enough to get used to it.
If any investment is to be made, get some comfortable furniture.
Pachmayr comes to mind.

Think twice, shoot once.