Single Shot
An action that holds one cartridge at a time and must be reloaded by hand between shots, favored in benchrest and some ELR rifles.
A single-shot rifle uses an action with no magazine: the shooter loads one round directly into the chamber, fires it, then extracts the case and loads the next round by hand. Because there is no magazine well or feed ramp cut into the receiver, the action body can be left solid and stiff, which is exactly why the design endures in precision circles.
That rigidity is the draw for benchrest competitors and some extreme-long-range builders, where every fraction of consistency counts more than rate of fire. A single shot also lets the shooter seat very long, heavy bullets that would never fit a magazine, and it forces a deliberate pace that suits load testing. The trade against a repeater is obvious: there is no quick follow-up if the first round misses.