The PPK/S was developed following the enactment of the Gun Control Act of 1968 (GCA68) in the United States, the pistol's largest market (Hogg 1979:164). One of the provisions of GCA68 banned the importation of pistols and revolvers not meeting certain requirements of length, weight, and other "sporting" features into the U.S. The PPK failed the "Import Points" test of the GCA68 by a single point. (See image of ATF Form 4590 for the complete list of qualifying points). Walther addressed this situation by combining the PP's frame with the PPK's barrel and slide to create a pistol that weighed slightly more than the PPK. The additional ounce or two of weight of the PPK/S compared to the PPK was sufficient to provide the extra needed import points.
Because U.S. law allowed domestic production (as opposed to importation) of the PPK, manufacture began under license in the U.S. in 1978; this version was distributed by Interarms. The version currently manufactured by Smith & Wesson has been modified by incorporating a longer grip tang, better protecting the shooter from slide bite, i.e. the rearward-traveling slide's pinching the web between the index finger and thumb of the firing hand, which was a problem with the original design.
As of 2007, the PPK/S is offered in the following calibers: .32 ACP (with capacities of 8+1 for PPK/S); or .380 ACP (PPK/S: 7+1).