I have a camo Nova with a rifled barrel for sabot slugs. Mounted a scope this year (not cantelver) and am using Hornady SST ammo. I chose the Hornady ammo due to its flat shooting characteristics.

At 100 yards, the shots were all over the paper. I'm guessing 6 - 8 inch groups. So today, I'm going back to the range with some more ammo to find if something else that will hopefully give respectable accuracy. I hope the accuracy problem is not from the shotgun or this could be expensive.

My smooth bore mossberg with rifled slugs was more accurate. Seriously.
Follow up to my review:
Spent over $100 on ammo to try to determine which was the most accurate. Nothing would get under 4 inches at 50 yards. I was able to take down a deer at 25 yards, but had no confidence over that distance.
My other major complaint with that gun. When trying to be quite, the guns forearm rattles loudly against the barrel if moved. Listen to it at the store and you'll agree. Traded it in on a Browning BPS and I'm now completely satisfied with my deer hunting slug gun. 2" at 100 yards with a variety of ammo. I am using the Hornady stuff and like it.