A slide action is a gun design where the motion of a movable forearm is transferred to the action to cycle the gun.¹

aka:

• • pump action
  • trombone action

guns that use a slide action:

• • Remington Model 760 GameMaster (centerfire rifle)
  • Remington Model 870 (shotgun)
  • Remington Model 7600 (centerfire rifle)

1. “Glossary.” ⇒ Sporting Arms and Ammunition Manufacturers’ Institute. Ed. SAAMI’s Technical Committee. Web. 15-18 Jan. 2011.