The Lefever automatic revolver, also known as the Union automatic revolver, is a French-American revolver.
The revolver was designed by Charles F. Lefever and began production in 1909 and ended in 1912, marking Union Firearms Company's exit from the handgun market. It was marketed around the same time as the Reifgraber pistol. The revolver was considered a commercial failure with only about 300 made due to the cost of production being too high.
The Lefever is an automatic revolver similar in design to the Webley-Fosbery automatic revolver with a shrouded hammer.