I have a Thompson-Center TCR-87 with a 20-ga rifled barrel. My records show that over the past few years I've gotten 38 deer with it, mostly does. Of those, 11 were at ranges of 150 yards or further. The furthest was slightly past 200 yards, and at longer ranges almost all were measured with a laser rangefinder. I shot 2 deer with big lead slugs in brass cases but the rest were with Winchester and Hornaday sabot loads. For broadside shots through the chest I don't think there is any advantage of using a 12-ga. Typically the deer run 50 yards after being hit. However, two fairly large bodied bucks went about 200 yards. One of those was not hit through both lungs. On only one shot did the sabot slug not shoot through the deer. That deer was a small one directly facing me at about 50 yards. The slug entered the front of the chest and was found under the hide a couple inches from the rear vent. For a large buck running directly away, I am not sure one could shoot it in the butt with a 20-ga sabot slug and be sure the slug would get to the vital areas of the chest cavity with enough remaining velocity to do much damage. Anyway, if one plans to shoot deer running away, maybe a 12-ga with heavier slugs would be a better choice. I think the lower recoil of the 20-ga is an advantage as 12-ga guns with slugs often recoil terribly. I've had to shoot from some awkward positions and it was nice to not have to worry so much about possibly being cut by the scope, and I am not particularly recoil sensitive. My long range set-up for deer during the rifle season is a .338-.378 Weatherby without a recoil brake. Around here it is more difficult to find the good 20-ga slugs. The gas station/quick shops usually only carry the old fashioned 12-ga slugs and not all the gun shops have a complete selection of sabot 20-ga slugs. I make sure I have enough before season begins.
