Double Action
A type of reloading action (single shot, integrated manual reload)
Double-Action is normally reserved for revolvers these days, although several airsoft NBB replicas use a double-action to reload their shots after reloading.
To reload a double-action gun, you simply pull the trigger. The trigger is linked to the reloading mechanism which loads the BB in to position before the trigger has been pulled all the way back. When the trigger reaches its rear-most point, the shot is fired. This reloading action can make the trigger more difficult to pull and can lead to lower effective accuracy.