The 590S will cycle mini shells. The regular 590 will need the OpSol mini shell adpater to cycle mini shells. budsgunshop.com/product_info.php/products_id/36595/opsol+texas+miniclip+mini-clip+for+mossberg+500+590+12+gauge+1+round+polymer+black+finish ,
Stay safe & have a great day!

Hi and welcome. Yes Sir, the 590S models were designed specifically to cycle mini-shells reliably without needing an adapter. Cheers, stay safe and enjoy!

Mini shells without an adaptor.

The 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. .the 590 will not cycle the 1.75 inch mini shells without aftermarket adapter https://opsolmini-clip.com/