7 weapons match your filters.
1887
The 1887 is a lever-action shotgun with a seven-shell tube that you can extend to ten. It deals solid close-range damage but works the action slowly, so it rewards careful shots over panic fire.
1887 Sawed-off
The 1887 Sawed-off is a cut-down lever-action shotgun built for hip-fire at point-blank range. FND Vanguards, Engineers and Special Forces Snipers carry it, and Rodolfo Claudia's insurgency rewards its unique Bases Loaded version.
KSG
The KSG is a semi-automatic shotgun with a 15-shell capacity, so you can keep firing in a close fight. Buy it from Juan's arms dealers, or get its unique Excavation Execution from The Long Drop treasure hunt.
M133
The M133 is a pump-action shotgun that can drop most unarmored or lightly armored soldiers in one close shot. El Rubi is its unique version, built by a Yaran furniture maker.
RMS-18
The RMS-18 is a rank 4 shotgun with a 12-shell magazine, so you can keep firing longer than with most shotguns. You can buy it or loot it from FND chests.
SBS
The SBS is a two-shell double-barrel shotgun that hits hard up close. Its unique The True Loyalist comes from a treasure hunt, and it also appears in Vaas: Insanity.
SPAS-12
The SPAS-12 is a shotgun you earn from the Passing the Torch treasure hunt. It also appears in the Lost Between Worlds DLC, which adds a Blue Fractured version.