The AMT Backup was first known as the OMC Backup. This early variant was produced in .380 ACP caliber. The AMT Backup is a small semiautomatic pistol available in a wide range of calibers: .22LR, .380 ACP, .38 Super, 9x19mm, .357 Sig, .40 S&W, .400 Corbon and .45 ACP have all been offered. This pistol was designed to be carried as a backup gun by law enforcement and security professionals or anyone desiring a small concealable weapon.