A safety latch assembly locks a firing tray mechanism and prevents it from firing a primer prematurely if a breech is not safely closed. The safety latch assembly includes a latch body, a latch hook for locking a firing mechanism tray, and a shaft that connects the latch body to a housing. A torsion spring is secured to the shaft, to bias a first pin towards the firing mechanism tray. A second pin couples a circular rack to the firing mechanism tray.