Page 89 - FAT 105 4.17 MOODLE

French MAS-38 both employ the
off-axis action design. The bolt of the
Jatimatic moves at an upward angle to
the bore, while the MAS’s bolt moves
at a declining angle. Recently, the ac-
tion has been utilized by the KRISS®
Vector. The Vector can be configured
as a pistol, rifle, or SBR, and has
multiple chamberings from 9x19mm
NATO to 10mm Auto.

FLUTED CHAMBERS

The fluted chamber is a design feature that is
found most commonly with blowback actions.
The purpose of the fluted chamber is to ease
Figure 12: A fluted chamber.
the empty case’s extraction. The system utilizes
gasses from the discharging cartridge to flow
between the cartridge case and chamber and to
prevent the case from sticking.
The fluted chamber is very advantageous for
The floating chamber design features slots cut blowback firearms because they tend to be very
around the chamber parallel to the bore, typi- finicky with various types of ammunition. Any
cally spaced farther forward in the front of the friction between the cartridge case and the
chamber. During discharge, a small amount chamber walls can dissipate enough energy
of high pressure gas is channeled to the flutes, from the system to cause malfunctions. The sys-
which creates a pillow of air for the case to float tem has worked so well for the blowback-style
inside the chamber. This pillow of air prevents action that other action types, like the recoil and
the cartridge case from sticking to the chamber gas-operated actions, have begun to adopt it to
walls and makes extraction much easier. help with harsh extraction.

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