The Model 1100 is made in 12 gauge, 16 gauge, 20 gauge, and .410 bore.
Articles on the Remington 1100
If there has ever been an all-around champ of shotguns it must be the Remington 1100. It was the first widely successful gas-operated semiautomatic shotgun; heck successful isn’t even close to being superlative enough. Hugely successful is modest praise.