Replacing the barrel could be quite an investment over what you're already putting into it. A barrel from Numerichs isn't likely to just screw on and have proper headspace, so some machine work may be required.
I agree with Savage99F358, if it's already grouping OK, without even playing with reloads for it, you already have a great 99 to hunt with...how bad was the paint removal? your gun didn't come out of Oregon did it?
