The attachment mechanism on the factory 590S cartridge arrestor is not very robust, so we modified our patent-pending Universal Minishell Adapter to fix this problem, and we are now offering it in an upgrade kit for the 590S.
This kit is compatible with any Mossberg 12-Gauge 590S pump-action firearm with machined grooves in the receiver. Please refer to the picture or the installation video below to confirm your firearm's compatibility, but we've never seen a Mossberg pump-action firearm without these grooves. The arrestor is constructed from vulcanized thermoplastic rubber, and the follower is machined from solid 6061-T6 billet aluminum.
*The Cartridge Arrestor and Magazine Follower are optimized to function as a pair, but the factory and other aftermarket followers may function as well for those that do not wish to use the one provided.