The Remington 1100 is a gas-operated semi-automatic shotgun

Semi-automatic shotgun

A semi-automatic shotgun is a form of shotgun that is able to fire a cartridge after every trigger squeeze, without any manual chambering of another round being required...

, popular among sportsmen. The Remington 1100 was the first semiautomatic shotgun to feature significant reduction in felt recoil, light weight and reliability.
Designed by Wayne Leek and Robert P Kelley, the Remington Model 1100 was introduced in 1963 as a successor to the Model 58 and 878 gas operated shotguns. The Model 58s had supplanted the recoil operated Model 11-48

Remington 11-48

The Remington 11-48 is a semi-automatic shotgun manufactured by Remington Arms as the first of the "New Generation" semi-autos produced after World War II. The Model 11-48 was released as the replacement for Remington's Model 11...

, which retained the long recoil action of John Browning

John Browning

John Moses Browning , born in Ogden, Utah, was an American firearms designer who developed many varieties of military and civilian firearms, cartridges, and gun mechanisms, many of which are still in use around the world...

's original design, present in the Remington Model 11 and the Auto-5

Browning Auto-5

The Browning Automatic 5, most often Auto-5 or simply A-5, is a recoil-operated semi-automatic shotgun designed by John Browning. It was the first successful semi-automatic shotgun designed and remained in production until 1998...

.