Not all but most of the ones SB tactical makes apparently have been deemed illegal by the atf.

I've been wanting one of these ever since I knew they were available, but Sig has been out of them forever. I even set up an email alert with them when they came back in stock back in March and never got an email. Finally got a tip on another forum that Osage County Guns had them so I ordered...

The rifle is brand new out of the box. During cleaning and inspection before firing, saw what I thought to be a crack in a removable piece just behind the barrel chamber on the upper. Sure enough it’s a crack. Looks like a mim part to me. I am not sure what the piece is called. It is not shown...