Using smokeless powder in a barrel not designed for it, despite the fact that the action is, is not a healthy thing to do. The only ML designed, tested, built and PROOFED to handle smokeless powders is the Savage 10ML and 10ML-II. Besides that, 2100fps with a 240 grain XTP isn't that great when you consider that a somewhat reduced load of N110 (40.5gr) in my 10ML-II pushes a 300 grain SST/ML to a chronographed 2250fps in warm weather. Of course, if you'd rather have the convienience of smokeless without the added recoil that the full throttle loads produce, it's very easy to reduce the loads and duplicate T7 or Pyrodex performance levels with significantly LESS recoil (because you're not pushing 70-120+ grains of powder down the barrel, less ejecta=less recoil).
Seems like a great idea to me, assuming the pressures generated fall within the limitations of the barrel. Smokeless would probably help with the dreaded "crud ring".
I can tell you with certainly that smokeless leaves no 'crud ring' whatsoever. In fact, it leaves virtually no fouling at all. I can shoot 40 shots out of my 10ML and never swab the bore once, and the 40th shot will load as easily as the 2nd. That isn't to say that periodic cleaning isn't required, because there is, at least with full power smokeless loads, enough plastic fouling to cause groups to open up. I generally clean with a nitro solvent and bronze brush every 10 shots or so to keep accuracy up to par.
Mike