** THIS KIT UPGRADES LEGACY 12-GAUGE MOSSBERG 500, 590 OR MAVERICK 88 FIREARMS TO 590S FUNCTIONALITY **

This kit contains our Patent Pending Universal Cartridge Adapter and Low-Drag No-Snag Magazine Follower which allows cycling of 1-3/4" Minishells up to 3" Magnums in the same magazine.  The adapter is constructed from vulcanized thermoplastic rubber, and the follower is machined from solid 6061-T6 billet aluminum.  This kit is compatible with all Mossberg 12-Gauge pump-action firearms with machined grooves in the receiver (refer to the picture or the installation video to confirm your firearm's compatibility).

Please note there may be a short break-in period for some adapters after installation.  Cycle a few magazines of full-size shells if you initially experience issues with 1-3/4" shells, please reach out to us if problem persists.