I’ve put 3” slugs through both my spouse’s 590 and my 500 with no issues. The only fte issues have been with light target loads. If you don’t want to send the gun back to Mossberg, find a good local gunsmith.
Three and four.
It’s done, I sent them an email asking for a return number.
Thanx all, great minds all.
I do not see the need for 3 inch slugs. The 2 3/4 inch are the same diameter and the hard cast have plenty of velocity and penetration. Where I like the 3 inch is buckshot. in #4 buck you can go from 24 pellets to 42 pellets. In 00-buck you go from 9 to 15 pellets.