Tap, rack, bang
Tap, rack, bang (TRB) or tap, rack, and go (TRG) is jargon for the response to a failure to fire in a firearm with a removable magazine. This is designated as an "Immediate Action" and involves no investigation of the cause (due to being under fire in a combat or defensive situation), but is effective for common failures, such as defective or improperly seated ammunition magazines.