In the lower 48, I can't think of anything I'd want to do with a handgun that I couldn't get done with a 240gr LBT at 1,100fps. And I have no doubt at all that the GP-100 could handle that load.
Now I personally don't care for "magnums" (and that load is in the magnum realm) under 4", but I could "suffer" along with that beautiful GP-100 at 3". I think FOR ME, I would drop the above load to 900fps and call it good for anything I'm likely to do with that particular revolver.
