Some methods use impact to retract the lockingbolt, most of which are destructive.
个别方法利用冲击力来使锁闸缩回，但大多数都会令材料解体。
2
The BRG-15 had conventional, gas operated action with rotating bolt, locking into the barrel extension.
该担心现有- 15接受传统，燃气经营与旋转螺栓行动，延长锁入桶。
3
After a free movement of about 22 mm (. 9 inch) the bolt carrier swings the locking piece up from the locking recesses in the receiver, and thus unlocks the bolt.