What is the locking system of the SCAR-H MK17?

What is the locking system of the SCAR-H MK17?

• A. Tilting bolt
• B. Rolling bolt
• C. Rotating bolt
• D. Fixed bolt

Answer: (C)

Rotating bolt locking is used here. The SCAR-H MK17 locks the breech by the bolt head turning to engage locking lugs in the receiver, providing a strong seal for the 7.62×51 mm round. When a shot is fired, the gas piston drives the bolt carrier rearward and a cam on the bolt rotates it to unlock; the bolt then retracts to extract and eject, and on the next cycle it rotates back into the locked position to chamber a new round. This rotating mechanism distributes locking forces around the bolt and receiver, giving reliable operation under sustained fire. Tilting bolt and rolling bolt systems use different motion to lock, and a fixed bolt does not rotate to lock, so they aren’t how the SCAR-H MK17 is designed.

Rotating bolt locking is used here. The SCAR-H MK17 locks the breech by the bolt head turning to engage locking lugs in the receiver, providing a strong seal for the 7.62×51 mm round. When a shot is fired, the gas piston drives the bolt carrier rearward and a cam on the bolt rotates it to unlock; the bolt then retracts to extract and eject, and on the next cycle it rotates back into the locked position to chamber a new round. This rotating mechanism distributes locking forces around the bolt and receiver, giving reliable operation under sustained fire. Tilting bolt and rolling bolt systems use different motion to lock, and a fixed bolt does not rotate to lock, so they aren’t how the SCAR-H MK17 is designed.