I drew a bull bison tag for the Lower Brule reservation in SD, this fall.
The guide says he has had people use shotguns before, but had no suggestions on loads.
I am shooting a 20ga.
Was considering the DDupleks steelhead, or the Brenneke Green lightning.
Any input appreciated. Am I an idiot for considering using a shotgun?

I should be a doable thing.
DON'T use any steel anything, steel sucks.
Your over thinking it, Just use an all lead slug 1 oz., or 7/8 in a 20.
keep it 50 yards or less and it'll be your Bison.
Don't mess with a sabot you want all the mass you can get. A foster type or Brenneke in my mind would be the best , at that range you can use your smooth bore and bird bead sights. I shoot full size slugs through my FULL choke all time with absolutely no problems.
PLEASE don't use any kind of shot If you HAVE to shoot Non tox use Tungsten in as big a shot you can find .
USE A LEAD slug !!!!!!!!!

Brenneke for the win!

That would be my pick too.

OMG they are good eatin'!!!!!

I raise them for meat. A .22 just behind the ear is all you need. Then slit the throat, hoist them up and bleed out.

Thanks guys. Brenneke it will be.

No, you're not an idiot for using a shotgun, you're just limiting yourself to lesser distance, you're also limiting yourself using a 20G. A 20G will surely kill, it maybe a little under power for a Buffalo though.

A 2 ton animal, I do not want to piss off, It should be killed quickly.

Use a 12G rifled barrel.
As for DDupleks not a damn thing wrong with them. I got my elk with one using the DDupleks Broadhead. One shot at 50 yard and the elk went down on the spot.
Oh and it is very accuracy, got my browning auto 5 clover leafing at 50 yards with open sights out of a Hastings rifled barrel.