Question

Double action skill​

Answer 1

Double action (or double-action) refers to one of two systems in firearms where the trigger both cocks and releases the hammer.

Double-action only (DAO) firearms trigger: The trigger both cocks and releases the hammer. There is no single-action function and the hammer will return to its decocked position after each shot.
Double Action Kellerman (DAK): A varant of traditional double-action used on certain SIG Sauer semi-automatic pistols. DAK triggers have a long stroke with 29 N (6.5 lbf) pull. However, if a user shooting under stress short-strokes the trigger by only releasing it halfway, the trigger will reset, but with a 38 N (8.5 lbf) pull. This temporary increased trigger pull is intended to prevent negligent discharges.
Traditional double-action – or double-action/single-action (DA/SA) – firearms trigger: The trigger combines the features of both a double-action only and a single-action only trigger.