A method and apparatus for discharge blocking device compatible with a firearm having a magazine housing and a trigger bar, the discharge blocking device comprising, a cover, having a shape compatible with the magazine housing, abase, covering a locking mechanism, and a locking element, at least partially accommodated in a channel inside the cover, wherein the locking element is configured to allow movement within the channel between locked and unlocked states in order to allow blocking the trigger bar of the firearm, and wherein the locking element is at least partially accommodated inside the wall of the cover and configured to at least partially rotate between locked and unlocked states about an axis that is aligned with the longitudinal dimension of the cover, in order to allow blocking the trigger bar of the firearm with the blocking segment.