The Mossberg 20-gauge refers to shotguns chambered for the 20-gauge shell, a popular choice for hunters, sport shooters, and home defense due to its manageable recoil and versatility. Mossberg produces a range of shotguns in 20-gauge, with the Mossberg 500 and Mossberg 590 being two of their most well-known models. Both are available in 20-gauge versions, and they are widely respected for their reliability, affordability, and ruggedness.