Safety mechanism retrofittable into existing firearms without changing external shape of firearm

摘要

A modular safety device configured for retrofitting a firearm, the firearm having a barrel including a muzzle and a chamber at a distal end of the barrel, the modular safety device comprising a blocking rod configured to fit inside the barrel including inside the chamber and to block entry of a cartridge into the chamber, the blocking rod having a lock configured to lockingly affix a locking portion of the lock to the barrel; and a biometric identification system integral to a proximal end of the blocking rod adjacent the muzzle and having a user interface surface accessible for a user to input biometric data of the user, wherein the safety device is configured to be within the firearm such that addition of the safety device to the firearm either does not alter an external shape of the firearm or merely juts slightly out of the muzzle.