This vest-pocket pistol overcame economic and legal obstacles. In the early 20th century, Colt peddled a line of vest-pocket pistols developed by John Browning. ... The Junior was little more than a rebranded Astra Cub, a small pistol Colt introduced in 1954.
The standard Junior came chambered in .25 ACP. There was also a version that fired .22 Short. The Junior featured a six-round, single-stack magazine and made use of a simple blowback action.
The Junior lacked the grip safety of the Vest Pocket Hammerless but did have a manual thumb safety. A push-button magazine catch at the bottom of the left grip panel released the magazine.