Just to be clear, I deburr and chamfer (sort of the same thing) along with the bell that the M die produces, if you set it deep enough. It may be that if you produce enough bell you won't need to chamfer, or not as much. It seems that belling and chamfering work hand-in-hand.
In any event, you'll know you're good to go when you can seat a bullet smoothly without shaving lead. You'll probably have to tinker to get just the right combo.
Paul
