11. The proprietary bolt is a three-lug design that locks onto the barrel extension leaving the upper receiver unstressed. 12. After firing a round, the initial recoil impulse drives the barrel, barrel extension , and bolt to the rear. 13. Megatron, the Decepticon leader, originally transformed into a realistic Walther P38 pistol with stock and barrel extensions and scope. 14. It has five interchangeable parts : a barrel extension , flip up sight, dual-mode light beam, stock and main blaster. 15. The bolt is held in battery by two sliding cylindrical rollers that engage locking recesses in the barrel extension . 16. The Model 1200 was the first shotgun to utilize a rotary bolt with four locking lugs secured within the barrel extension . 17. While the bolt and barrel are returning forward, a cartridge-rammer lever, mounted on the barrel extension , pivots forward, loading a fresh cartridge. 18. As the bolt's locking lugs move past the barrel extension , the cam pin twists into a pocket milled into the upper receiver. 19. This twisting action follows the groove cut into the carrier and forces the bolt to twist and " lock " into the barrel extension . 20. The bolt continues pushing the round into the chamber and locks up when the lockring rotates and locks the bolt and barrel extension together.
