tiltingbolt

Tilting bolt is a bolt-locking mechanism used in some bolt-action firearms. In this design, the bolt head tilts slightly as the bolt is closed, engaging locking lugs in the receiver by angular displacement rather than by rotating the entire bolt head. This contrasts with rotating-bolt designs, where the bolt head rotates to lock.

During a firing cycle, the bolt is moved rearward to extract and eject the spent cartridge. As it returns forward, the tilting action causes the bolt head to lock, pressing the bolt face against the cartridge case and sealing the breech. Unlocking occurs when the bolt is drawn back again, releasing the lugs.

Advantages of tilting bolts include a potentially simple locking interface and robust engagement with varying cartridge dimensions. The arrangement can allow a compact receiver and straightforward manufacture. Disadvantages include timing sensitivity of the tilting action, wear in the cam or pivot, and greater complexity compared with many rotating-bolt designs.

Tilting-bolt systems appeared in several early bolt-action rifles and are found in some niche or proprietary designs. Today most mainstream rifles use rotating bolts, but tilting bolts are of historical and design interest to firearms engineers and historians studying the evolution of locking mechanisms.