12 Ga sabot slugs. I was military and hunted in my home state of Illinois pre-straightwall laws. Loading your own is not really feasible, and with as few as you shoot why would you? My first was a Hastings barreled Rem 1100 with cantilever scope mount. My dad about had a good chuckle when I came home on leave and picked up 10 different loads, he knew the pain that was coming, benching a slug gun is not that fun. Some ran 5" at 50y, most were 2-3" then I put some Lightfiled's in one cloverleaf. Done deal. Took a non-typ 8pt at 127y on Crab Orchard NWR. My dad ditched his 870 smoothbore with rifled slugs and saddle scope mount that year.
My Gloss Engraved 1100 was too nice to subject to deer hunting, so my next setup was an 870 SuperSlug, rifled with cantilever mount. It ran best with the Federal Barnes eXpander Copper solid. That is what I took the 8 pointer in my profile pic about 70 yards. Also in the Crab Orchard NWR. 1oz at 1500fps and check out the HP in those bad boys!