Common Actions on Shotguns
Shotguns have many options for types of actions including pump action, semi-automatic action, and break action. They also use a break action as either a single barrel or double barrels. The double barrels can be arranged horizontally (side-by-side) or vertically (over-under).
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Over-and-under shotgun
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Semi-automatic shotgun
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Pump-action shotgun
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Top view of break action side-by-side shotgun