During the 1950's the U.S. military experimented with alternative feeding devices for machine guns. One of the more interesting concepts that arose from those experiments was a triangular cartridge case. When stacked into a magazine, triangular cartridge casings took up almost 50 percent less space than traditional round cartridge casings.
While this was not further pursued by the military, an American inventor named David Dardick seized upon the concept to develop a new high capacity handgun for the commercial market. In the late 1950's Dardick acquired patents for both a triangular shaped cartridge called the "tround" (for triangular round) and a magazine fed handgun that would use it. Dardick then proceeded to develop and produce both the cartridge and gun.
Unlike a traditional brass cartridge, the tround casing was made of an extruded plastic, Celanee Fortiflex. This plastic was used to fill the gap between the triangular cylinder and the round projectile it encased.
The design of the gun was a hybrid. It had revolving cylinder of chambers like a revolver and a box magazine like a semi-automatic pistol. Unlike a conventional revolver though, Dardick's cylinder was enclosed inside the gun's frame and incorporated triangular shaped open chambers. This allowed the trounds to be fed into the open side of the cylinder from a magazine.
The revolving cylinder had three V-shaped channels spaced evenly in the cylinder that formed the gun's open chambers. The channels provided two sides of the chamber, and the gun's topstrap had a pre-stressed metal plate that completed the third side of the chamber.
The magazine fed the cartridge into a chamber near the bottom of the cylinder's rotation. When the trigger was pulled the cylinder rotated like a conventional revolver. At the top of the rotation the open chamber would be closed off by the gun's topstrap, allowing the cartridge to be fired. As the cylinder rotated, the spent "tround" cartridge would fall out of the cylinder through an opening in the other side of the gun's frame.
Despite the revolutionary design of the round and the firearm, the ultimate demise of the Dardick was due to its poor aesthetics and reliability. The gun simply looked ugly, and the plastic cartridges warped over time and would not chamber properly, resulting in the cylinder locking up when it rotated. Ultimately Dardick's concept failed, and his corporation folded in 1962 with very few guns actually produced and sold.
Today the few guns that were produced are highly sought after as unique collectibles, bringing a premium price. Though rare, the NRA National Firearms Museum has a Dardick 1500 in its collection, featuring the carbine conversion kit along with the gun.