I have a B mag riser and a newer Gainesville wood riser. The alignment screw in the limb pockets has a different diameter head on it, so to use the new limbs on the old riser (and vica-versa), I had to change out the screws. Surely a person could find some screws at a hardware store if they didn't have another riser to interchange them with. (?)
My old limbs are #3's at 55#'s (rose tips). I must be different than most, because I prefer the #1's on a B riser--like the shorter bow, and also highly prefer a longer riser and shorter limbs (as opposed to an A with #3's).