my cousin has taken a few deer with my 20" H&R and winchester slugs and brenneke tactical home defense slugs. the brennekes group the best followed by speer LE and then the winchesters.
I use to use a PUMP MOSSBURG 500 and shot Brenneke 2 3/4" and if I still shot a slick bore barrel that is ALL I would use.... Loved them !!!! But now with my Rem 11-87 rifled barrel I use Hornaday SST's 2 3/4" and they will reach out there and are tac drivers.... Hornaday SST's are best slugs for your money with a rifled barrel IMO....
Guess I'm different, when money was really tight I used cut shells and wax slugs with some degree of success.
Used an old Montgomery-Ward single shot I got from my Dad.
Now, whatever I find on sale in bulk in my Saiga 12.
My dad and I both shoot Winchester Super X slugs in our 870 smooth bores. They hold tight enough groups for us. My dad dropped his buck last year at 118 yards with them.
H&R rifled 20 ga single shot here. Won't shoot the expensive sabots worth a crap. Remington Buckhammers it'l put 2 shots touching at 100 yds. Go figure.
Another vote for Brenneke . They are absolutely devastating on a whitetail . These are my got to slug in a smoothbore . I don't use a 12ga very often , usually only on deer drive but if you connect on a deer it's game over .
I have the same gun, smooth bore rifle sights, and it also shot great with WW 2.75" Rifled Slugs. It shoots a 2-3" group at 50 yds no problem, and that's with open sights and my bad eyes. Only ever shot it at 2 deer, and it made quick work of them.
My Ithaca shoots Win and Rem slugs into the palm of your hand at fifty point of aim. Also shoot the same from 870 and a Benelli Nova with same great results. Tons of fun! Pumpkins and water jugs and steel swingers last weekend. Need to restock my stash now.
I dont think a rifled barrel would give much better results considering their cost. If looking into more range there are better choices than a slug gun.
I used to shoot Federal 2 3/4" 1 Oz out of a Mosssberg. Took many deer with that slug, usually my shots were under 50 yards. One time I did get a deer at 85 yards with those.......