Remington Model 878

The Remington Model 878, also known as the Automaster, is a semi-automatic shotgun manufactured by Remington Arms in the mid 20th century. It is a gas operated shotgun and was marketed alongside the related Model 58 and the recoil operated Model 11-48. The 58 was manufactured in 12 gauge only from 1959 to 1963 until it was replaced by the Model 1100.

Design
The Model 58 suffered from many design shortcomings compared to the contemporary Model 11-48 with which it shared many design features and parts. The 878 introduced an improved "self-adjusting" gas system compared to the Model 58 though it still operated similarly. Another change was in the carrier and bolt system which were now quite similar to the Model 870, thus the similar name.

While improved, Remington chose to retire the Model 58 and 878 quickly in favor of a new, more elegant design. The resulting Model 1100 immediately replaced the Model 58 and 878 and proved so successful that it soon also replaced the Model 11-48 and remains in production as of 2014, over 50 years after its introduction.