This is all very interesting. I originally asked the question because I recently acquired a used gun I was thinking of using as a slug gun too. However it is discontinued and the only barrels I can find for it are rifled.
I have shot rifled Brenneckes in the past and like them. I do know people who do not like sabots as they have had situations of very little or no blood trail with them. I will have to ponder my options.
Put a sabot where it needs to be 1/3 of the way up and the deer shouldn't go far and more than likely there will be a very good or at least visible blood trail.