Sep 30, 2014 · But as for stopping power, my old Sgt. would tell us that the Beretta 9mm would stop someone…eventually but the 1911 .45 was a “DRT”…as in “Dead Right There” I’m not going to turn this into a fanboy article about t.45 v 9mm v .40 but I do question the FBI’s motives. Aug 23, 2018 · There’s also the practical issue of feeding the gun; these days, .357 Sig practice ammo is about twice the cost of 9mm and around 50% more than .40 S&W. On the plus side, a lot of pistols chambered for .40 S&W can be converted to .357 Sig just by swapping out the barrel.