I have put 600 rounds through it so far. Other than a handful of winchester rounds not firing. As of late I have been using tul ammo with zero issues until tonight. The round fired but the shell stayed in the barrel and locked the slide up. Has anyone had this problem? Just caught off guard I have never had it happen.

Steel cased ammo. Not totally unknown for a fired case to get stuck. You can probably drift it lose with a wood dowel from the muzzle end without too much trouble. I carry an unsharpened #2 pencil in my range bag for that purpose. Once it backs up a bit, you should be able to pull the slide back.

I won't do it, but any minute someone will come along and tell you to not use steel case ammo in your Shield. It's an idea worth considering.

For target or range practice steel is fine. I've shot thousands of rounds of steel cased ammo without issue. When it starts getting stuck, that is an indicator to me that I need to clean the firearm. For self defense use I want either the cases to be polished and slick therefore I find nickel to be best followed by clean shiny brass and finally cleaned steel.