Just spoke to Chris at Guns and Gear. He said he has the Shield 40 barrels on order. They are now also out of 9mm barrels. He said we are now waiting for S&W to ship us both the 9mm and 40 Shield barrels. He said he did not think the 40 barrel would fit in the 9mm slide. I explained that the tab on the 40 barrel was wider, and needed to be made slightly smaller, and it would fit into the 9mm slide. He said he was not aware that was all that was needed to get it to fit.