This refers to a specific type of firearm: a rifle chambered for the 5.7x28mm cartridge and utilizing a bolt-action mechanism. The 5.7x28mm round is known for its high velocity and small caliber, originally designed for personal defense weapons. A bolt-action mechanism is a manually operated system where the user cycles the bolt to load and extract cartridges, generally prized for accuracy and reliability.
Combining the 5.7x28mm cartridge with a bolt-action rifle platform creates a unique firearm suited for specific applications. The inherent accuracy of bolt-action systems, coupled with the flat trajectory and armor-piercing capabilities of some 5.7x28mm loads, makes this combination appealing for varmint hunting and some competitive shooting disciplines. Historically, the 5.7x28mm round has been primarily associated with semi-automatic firearms. Its adaptation to bolt-action rifles demonstrates an evolution in its use and an expansion of its potential applications.