Single-action is a type of gun mechanism where a single pull of the trigger fires the gun. The single-action gun must be cocked manually before pulling the trigger.

It is possible for a gun to be both double-action and single-action.

aka:

• SA (acronym)

related:

• double-action
• single-action only

 

Footnotes / Sources:

“Glossary ⇒.” Sporting Arms and Ammunition Manufacturers’ Institute. Ed. SAAMI’s Technical Committee. Web. 15-18 Jan. 2011.