I haven't used slugs in many years, I moved out of New Jersey in 1989. I'm impresed with everyones claims of accuracy with rifled barrels and sabot slugs, these weren't an option when I hunted there. The one thing that bothered me was that most hunters don't bring their shotguns to the range to find out it's true capabilities. For example I have a plain barreled Mossberg 500 in 20 gauge. I masked off a thin line approximately 1/8 in to the right of center on the back of the receiver and painted it with flourescent green model paint. My gun shoots to the left and this corrects it, line the bead up with the line I painted will get the slug back on center. With birdshot I never knew that it shot 10 inches to the left at 40 yards. With this setup I can keep my slugs in a 6 inch group at 50 yards and I limit my shots to this range.
My "slug" gun is amazing when held to smoothbore standards. Does anyone remember the old Marlin Goose guns? Bolt action 12 gauge with a 36 inch barrel. I was given one as a kid. I cut the barrel to 20 inches, glass bedded the receiver, drilled and tapped the receiver, added a peep sight (visible with the scope mounted), machined annd mounted a front sight, refinished the stockand machined a custom scope mount that held the scope high and to the left in order to clear the bolt. This gun opened my eyes to the differences in ammunition. I can hold three inch groups at 100 yards using Wichester 1 ounce slugs and I would have no problem shooting out to 125 yards. Remington slugs won't even hit the target at 100 yards, I get a spread of about 3 feet at this distance. I'm told that this is due to different diameter slugs, the winchester are oversized and crush down to size in the forcing cone in front of the chamber and the remington slugs are undersized and they expand to fit the chamber. My hunting partner uses a gun with a modified choke and gets better groups with the remington slugs.
These old foster style slugs do impressive damage to deer. I killed a buck at 75 yards one time quartering towards me, the slug broke his left shoulder, traveled the length of the body and broke his right femur and lodged under the skin. The slug was almost an inch in diameter and it still weighed one ounce. It's hard to improve on that kind of performance.