Tap rack bang
Tap, rack, bang (TRB) is slang for the response to a failure to fire in a semi-automatic firearm. This is designed as an unhesitating "Immediate Action" and involves no investigation of the cause; but is effective for common failures, such as defective ammunition or improperly seated magazines.
- Tap - to tap the magazine. This is to ensure that the magazine is properly engaged in the firearm so that it feeds properly. As typically taught in tactical firearms courses, the "tap" is considerably more than a tap and in the case of a semiautomatic pistol is usually accomplished by slamming the gun hard into the palm of the other hand, magazine end down.
- Rack - operating (cocking or cycling) of the slide of the firearm. This will serve to eject a misfired round, which could be a possible cause of the stoppage, and chamber the next round.
- Bang - aiming and firing the firearm again.
- "IMMEDIATE AND REMEDIAL ACTION - M9 SERVICE PISTOL", Page 7, Marine Corp Development Command