Every shotgun, regardless of smoothbore or fully rifled will shoot more or less accurately depending on configuration. 2 3/4" versus 3", handloaded and/or factory. Find the one that shoots the best for you.
Try
www.DixieSlugs.com
James is the former VP of the S&W Ammo company and he manufactures, in my opinion, the finest 12ga slugs I've ever shot. I am a full time police officer and "his" slugs are in my duty 870 everyday. Try them, you won't be disappointed.
HiVelocity