Been there, done that, no go. Even tried filing down some 50 BMG / .308 sabots to fit in a ML and shoot 125gr Ballistic Tips. Result was either a keyhole or bullet not separating from the sabot at all (much different sabot design of course).

If you want to do that, you'll have to do what some guys are doing and making a custom ML with faster twist. But most of those guys are swaging/knurling bullets to shoot them sabotless as ML sabots seem not to work well in faster twist guns -- I think they start jumping the rifling.