The Remington Model 878, also known as the 878 Automaster, is a

gas-operated Gas-operation is a system of operation used to provide energy to operate locked breech, autoloading firearms. In gas-operation, a portion of high-pressure gas from the cartridge being fired is used to power a mechanism to dispose of the spent ...

semi-automatic shotgun made by

Remington Arms Remington Arms Company, LLC was an American manufacturer of firearms and ammunition, now broken into two companies, each bearing the Remington name. The firearms manufacturer is ''Remington Arms''. The ammunition business is called ''Remingto ...

from 1959 to 1963. The Model 878 was based on the company's previously introduced Model 58, both of which were succeeded by the Model 1100.

Design

The predecessor to the Model 878, the Model 58, was a new semi-automatic design for Remington, being a gas operated system rather than the long recoil operation system designed by

John Browning John Moses Browning (January 23, 1855 – November 26, 1926) was an American firearm designer who developed many varieties of military and civilian firearms, cartridges, and gun mechanisms many of which are still in use around the world. He m ...

and used in the famous Browning Auto-5 and Remington

Model 11 A model is an informative representation of an object, person or system. The term originally denoted the Plan_(drawing), plans of a building in late 16th-century English, and derived via French and Italian ultimately from Latin ''modulus'', a mea ...

and Model 11-48. The Model 878 introduced an improved "self-adjusting" gas system, a notable improvement over the Model 58, which required the gas system to be manually adjusted for different types of ammunition. Barring this and cosmetic differences, the Model 58 and Model 878 are virtually the same, with both models essentially being gas operated versions of Remington's

pump action Pump action or slide action is a repeating firearm action that is operated manually by moving a sliding handguard on the gun's forestock. When shooting, the sliding forend is pulled rearward to eject any expended cartridge and typically to coc ...

Model 870. The gas system on the Model 878 utilizes a gas piston, which operates by tapping combustion gases from two gas ports in the barrel ring and directing the gases down into the piston, housed in the magazine cylinder. Rearward motion of the gas piston actuates the action bar which also moves rearward to open the bolt, allowing the spent shell to be ejected while moving a new cartridge from the magazine tube into the receiver. To complete the cycling of the action, the piston return spring moves the piston and the action bar forward, closing the bolt and moving the cartridge into the chamber. The gas system design found on the Model 878 (and other shotguns such as the Winchester Model 1400) has a notable disadvantage. Housing the gas piston and piston return spring inside the magazine cylinder effectively reduces the capacity of a tube magazine of a given size when compared to other gas or manually operated systems. The shortcoming in the design of the gas system on the Model 878 was addressed with an updated gas system found on Remington's Model 1100, making both the Model 878 and any other shotguns using a similar design technically obsolete.

References

External links

Remington 878 Automaster
via

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Remington Arms firearms Semi-automatic shotguns of the United States Weapons and ammunition introduced in 1959 {{Shotgun-stub