Two prototypes in .45 ACP were originally manufactured by DWM Luger for the U.S. Army Trials in 1906 that eventually gave us the Colt 1911. Of the two .45 ACP Lugers submitted to the US Army, only one, marked serial number 2, is known to have survived. Serial number 1 is assumed to have been discarded, possibly damaged after the initial trial. For unknown reasons, DWM (Deutsche Waffen- und Munitionsfabriken Aktien-Gesellschaft) withdrew from the trials after the first round of tests. At least three more of the .45 ACP Lugers were made, one a carbine bearing serial number 21.Most recently these handguns have been valued in excess of $1 million. One of the most rare and expensive handguns in the world.