RE: 20 guage or .12 guage slug gun?
I purchased a slightly used 20 gauge 870 express cantilever synthetic last winter and on the advice of the gun shop owner I bought some remington Buckhammer slugs.They group reasonablywell,Consistently less than 3 '' at 100 yds.Tried a number of other brands of sabots without success.I am quite confident in this combination out to 150 yards
Willy