I have used the Hornady slugs quite a bit. I've had excellent success with them on deer out to 175 yards. You definitely need a rifled barrel to shoot these slugs. Like all ammunition, some guns perform better than others with certain loads. Good luck testing.
I was shooting the hornadys through a Browning A-bolt 12 gauge. Browning no longer makes the gun but I had the barrel ported last year and it shot the hornadys quite well. I tried shooting those same slugs through my Tar Hunt 12 gauge and they didn't shoot worth a darn. I was shooting groups as small as 1.5" at 100 yards and and about 3 inches at 150 yards.
When calling coyotes, more often than not they will circle on a target they are
coming into and approach from the downwind side. Presumably they do this in
order to align what they smell, with what they are hearing.
This means that you should always have your downwind side camouflaged and have
an open shooting lane. If the area is heavily covered the coyote could come in
take a look and be gone, with you none the wiser.