When it was a problem to find hi-capacity magazines in 9mm, many shooters bought available M40 magazines and bent the feed lips down ever-so-slightly, and they would carry 12 rounds of 9mm. I guess you could open the 9mm magazine feed lips up a tad and use then in the .40, but I do not know of anyone who has done this.
P.S. .40 mags are used for the .357 SIG Steyr. If you have a .40 Steyr, you need only change the barrel to shoot .357 sig. Mags work interchangeably (sp?)
Regards, CGuns
P.S. .40 mags are used for the .357 SIG Steyr. If you have a .40 Steyr, you need only change the barrel to shoot .357 sig. Mags work interchangeably (sp?)
Regards, CGuns