The Semmerling LM4 is an American backup pistol.
The LM4 is developed from the LM1, LM2, LM3 and XLM models, with LM standing for "Lichtman Model", referring to the designer, Philip Lichtman, who applied for four different patents related to the design. However, the LM4 is the only model available to the public, and distributed in the early 1980s. The LM4 was designed to be a high-powered firearm that was very concealable, so the nominal military caliber of .45 ACP was used. The weapon was made manually operated so as to ensure flawless operation. Due to its high perceived stopping power, the LM4 was even offered to the US Army and government agencies. In 2005, the largest collection of Semmerlings, shown in the photo above, consisting of examples of the LM1, LM2, LM3, LM4 and XLM, along with all prototypes and drawings, was brought and displayed in the Smithsonian from 2005.
The Semmerling is a manually operated pistol consisting of only 33 parts, including screws.
Prototype version of the pistol meant to function semi-automatically.