Truer words were never spoken.There is no SAAMI specification for 40 S&W +P. That's nothing but a marketing gimick
Read and heed this advice, friend. If you want to hot rod, go ahead and get that 10. Otherwise, stick to the .40. It's plenty hot enough, and that USP is a fine pistol to shoot it in.If you really want that make sure you have a fully supported chamber (Glocks need not apply). The proper way to hot rod a .40 is to buy a 10mm.