While it hasn't gotten much attention, Mossberg just released a new model of the 590. It's called the 590S and can run the 1 3/4 Aguila mini shells in addition to 2 3/4 and 3 inch shells. You don't need to use a mini shell adaptor like the OPSol. The mini shells are a lot of fun and ballistically are comparable to the lower recoil defense shells but you can load more in the tube. The only downside I can see is the ugly white 590S lettering on the receiver!