The 870 was introduced in 1950, a mass-produced pump that replaced the old, hand-fitted and expensive-to-produce Model 31. The Model 500 came out in 1960 and represented a big departure and gamble for Mossberg, who, at the time, was largely known for .22 rimfire rifles. Both guns have gone on to serve in the field, in police cruisers and in battle. Each has its fans and haters. Both of these guns have been the first shotguns for thousands upon thousands of hunters, so it’s appropriate the Remington 870 is a 20-gauge youth model.