The Swiss Army was looking for a new pistol and the SIG P210 was too costly to manufacture. The Swiss Army wanted a cheaper semi-automatic handgun, that would still provide excellent functionality and a double-action trigger. SIG, in cooperation with a German arms company, J.P. Sauer & Sohn, developed a new pistol, the Pist 75 (as it was known in the Swiss Army service). The 9mm SIG-Sauer P220, debuted with various new and inventive features. It utilized a single column magazine holding eight 9mm rounds and had a 3.9 in. barrel.
A new German police standard, in the mid-1970s, prompted SIG-Sauer, Heckler & Koch, and Walther to develop new pistols that met the standard: the Walther P5, the SIG-Sauer P225 (known as the P6) and the Heckler & Koch P7. (In addition, Mauser had a design that never went into full production.) Each German state was free to buy whichever pistol it wanted to. Initially, the P220 was submitted; the P225/P6 was created to conform with the mid-1970s West German police requirements for its standard service pistol. The SIG-Sauer P225 was the least expensive (due mainly to the inventive design) and received the majority of the orders. To be able to manufacture that many handguns, SIG acquired a controlling interest in J. P. Sauer & Sohn in Eckenförde, Germany to manufacture parts for the P220. This is also where all P225s were manufactured. The only difference between the P6 and P225—the P225 (which was adopted by US civilian law enforcement) has a lighter trigger pull, whereas the P6's trigger pull is heavier. The P225 has tritium fixed sights; P6s had fixed sights only. Genuine P225s manufactured for the West German Police will have a "P6" stamp on the right side of the slide. A new police standard was adopted in Germany in 1995, and the P225 is in the process of being replaced. German police pistols can be identified by the hammer, which has small "ear" or "hook". According to section 7.7 of the German manual, the cutout is the Deformationssporn, which means “deformation spur”. This was a requirement of the West German Police for all their P6 pistols, to alert police armorers if the pistol was dropped on its hammer. Many of these surplus German police pistols have been imported into the U.S. recently. Because of its compact size, the P225/P6 is quite readily usable for concealed carry. In U.S. states where standard capacity magazines were prohibited, the P6/P225 was usually in high demand.