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.
Let me start by telling you the story of two Johns.
John number one went on a day hike with a couple of friends in the Cascade Mountains about an hour from Seattle. He somehow got separated from his buddies and became lost. John was dressed in casual cloths for a warm weather day hike and had nothing but a lunch with him. He spent three days in those mountains and luckily made it out to tell the story.
John number two, a friend of John number one, was much better prepared when...