Which of the following is a characteristic of the single-action revolver?

Cartridge must be loaded or unloaded through the loading gate.

Explanation:

Inside a typical single action revolver, the hammer cocked manually through a thumb. This action advances or rotates the cylinder for firing through the next round and locks the cylinder placing the chamber aligned with the barrel.

The trigger pulled actually releases the hammer and fires the round from the chamber. The cartilage must be loaded or unloaded via loading gate.