John Martz was a WWII US Navy veteran who spent a career in metalworking before turning his gunsmithing hobby into a full time occupation in the 1960s. He is best known for his custom Luger pistols, and today we have a selection of them to take a look at. They fall into three main categories - carbines, baby Lugers, and caliber conversions. Most notable of the caliber conversions are his .45 ACP guns, made by cutting a Luger frame in two and widening it (plus extensive work to convert the upper assembly parts). With the extremely scarcity and value of original DWM .45ACP Lugers, Martz's conversions are quite sought after.