Page 88 - FAT 105 4.17 MOODLE
P. 88
Figure 11b: Off-axis bolt travel delayed blowback action.
The bolt may be a single piece or use As the bolt continues rearward on
an additional carrier or slider. During its off-axis travel, it will extract the
discharge, when the cartridge case empty case from the chamber, eject
begins pushing back against the bolt, it, and cock the hammer/striker. The
the bolt will move in guides in the action/recoil spring will push the bolt
receiver/slide at an angle away from forward, stripping a fresh round from
the bore’s axis. This off-axis move- the magazine and feeding and seating
ment away from the direction of the it in the chamber. Once the bolt has
bolt’s momentum causes the bolt’s bottomed out against the barrel, the
movement to slow because of the me- chamber is fully closed.
chanical disadvantage that is created.
The off-axis bolt travel delayed blow-
The momentum in the bolt from the
back action has seen a fair amount of
discharged cartridge wants to push
use in modern times, with several fire-
the bolt rearward in-line with the
arms employing it. The design is pop-
bore, but rails or guides in the frame
ular because of the inherent design
direct the bolt in a direction away
advantage. Because the bolt does not
from the direction of momentum,
move in-line with the bore, the recoil
creating enough resistance to keep the
impulse is delivered in a different
chamber closed until the bullet has
manner, which significantly reduces
exited the muzzle and pressure inside
the amount of felt recoil. The Finnish
the bore has dropped.
Jatimatic 9mm submachine gun and
84
