In my experience recoil operated shotguns have very poor performance with slugs. I have had a buck special 16 gauge Auto 5 that would do about 10" groups @50 yards on a good day. Tried again with a shortened 12 bore Auto 5 even worse with absolutely no usable accuracy past 40 yards. I attribute it to the recoiling barrel and the movement it has. I doubt they never land in the same orientation to the receiver after each shot. Of course this does not affect shooting shot. The 11-48 is a good old dependable shotgun but shots under 35 yards with 00 buckshot may be your best option. Now if you do buy it try it with several brands of foster slugs it MAY be one of the few that actually performs. Just for the sake of conversation Remington did offer 26" factory smooth bore barrels with rifle sights for the 11-48 in the early 1960's.
Darryl