The Colt Model 1855 Revolving Carbine was a failure due to the design flaw that caused the live rounds to fire without being triggered.
The Mars Pistol featured an overcomplicated design and a heavy recoil, making it highly unpleasant to use.
The Glisenti Model 1910 had a weak construction that couldn't handle the power of standard 9mm rounds, leading to the pistol receiver exploding.
The Gyrojet Rocket-Propelled Pistol fired rocket-propelled bullets but suffered from high production costs, poor accuracy, and velocity falloff.
The Nambu Type 94 pistol had a poor design and low quality, making it unreliable and even dangerous for the user.