Both my S&W 4040PD and Sig P239 are chambered in .40 S&W. The P239 was designed from the ground up to be a .40 S&W and .357 Sig chambered handgun. So it is a bit beefier in that regards as a 9mm compared to a 3913. But the 3913 is a fantastic gun too and I enjoy mine; as well as my 4040PD.