Shotgun powerhouse Mossberg is apparently tired of people having to mod their 12 gauges to run mini-shells, so they now have the heavy-walled 590S series that eats them right out of the box.
The all-new 590S Series cycles 1.75-inch minis, 2.75-inch standard, or 3-inch magnum shells in any combination the user desires due to a redesigned anti-jam elevator and bolt slide combined with the addition of an energy-absorbing bumper. Repeat: these guns don't require the user to install some oddball adaptor to run those increasingly popular mini shells.
Mossberg has four variants of the 590S, including two traditional shotguns and two compact bird’s head-gripped Shockwave "firearm" versions.