I only have experience with the 20 gauge and that was in a Savage 220/3-9 Leupold. It was very accurate with the Federal 3" loads and 1.5" three-shot groups at 100 yards consistently. . Shot several whitetail deer with it but most of my shots were in the 50-80 yard range and I'm very particular about shot placement. The 20 gauge sabots passed completely through every time. I was confident that if circumstances were correct (broadside with a rest of some kind) 150 yard shots were very do-able. But that was my personal limit and never had to shoot that far. Your mileage may vary.
Sold my sabot shotgun when I moved west. But if I were doing it all over again, I'd go the 20 gauge route simply because A) they worked fine and B) I see no need for more recoil and/or bulkiness of a 12 gauge to double-lung with pass through on a 150 pound whitetail.
