Back in the 1930s Colt developed a few experimental fully automatic M1911 pistols. It is hard to believe that anyone thought that a .45 ACP machine pistol was a practical idea!

Note the Thompson Submachine Gun forgrip

The most famous fully automatic 1911 would have been John Dillinger’s which was chambered in .38 Super. His was a standard 1911 which he had modified so that it would be fully automatic.

Dillinger’s full-auto converted .38 Super. UPDATE: Some commenters have questioned if this photo is in fact of Dillinger’s gun.

More full auto .45′s over at Casatic.