Mike you can call S&W and see if they have any mountian gun barrels. I did this with a 3" M24 and turned it into a 6 1/2" target gun. This may be an option and then if sometime in the future you want the long barrel config back you can do it.

The M24 I have is a collectable revolver and if and when I want to put it back to original I can as S&W sends all parts back.