The 24" barrel would be the item of a different manufacturing method made by Mossberg to add to more correct shot placement when making use of factory made ammunition. The barrel is topped with a vented rib and outfitted with a HIVIZ TriComp fiber-optic front sight. Based on Miculek, The https://1upmushroombars00741.blogginaway.com/29757684/mossberg-590-serial-number-location-fundamentals-explained