The term 'bang out' is a phrase used to describe the act of quickly producing something, usually a piece of writing or typing. The crossword solutions for this term are WRITE (5 letters), TYPE (4 letters), and ZAP (3 letters). Writing and typing are both forms of communication that involve putting words down on paper or a computer screen. Zapping is an informal term for quickly sending a message, often electronically. All three of these activities can be done quickly and efficiently, which is what 'bang out' implies.