When reading through comments on a webpage or social media site, a response of +1 typically means the commenter agrees with something that was previously stated by saying he or she is one more person to state whatever point was made. O.F. Mossberg & Sons is applying a similar line of thinking to its 590A1 line of shotguns. Only for them, the +1 means one additional round of authoritative 12 gauge ammunition in the tube.
For 2016, Mossberg increased the standard capacity of its 590A1 shotguns from six rounds to seven while still keeping the magazine tube within the typical magazine length. I should note that Mossberg, like most companies, describe its shotgun capacities as including one shell in the chamber even though many people keep the pump action guns “cruiser ready” (full magazine, empty chamber.) This means the magazine-only capacity has been increased from five rounds to six.
There are four models of 590A1 shotguns affected. They include the basic model with a bead sight, the basic model with ghost ring sights, the Kryptek Typhon model and the mariner model. The additional magazine capacity does not affect the nine shot models – those remain unchanged.
All of the guns have a tri-rail forend for mounting a light. Additionally, all of these guns have a 18.5″ heavy wall barrel standard.