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chamber does not lock. Typically, the bolt blowback system. The delayed blowback
is replaced with a self-contained unit, system uses various methods to slow the
which incorporates a chamber, partial opening of the chamber. These methods
barrel, bolt, and action/recoil spring. include roller, lever, gas, chamber ring,
hesitation lock, toggle, and off-axis bolt
The floating chamber lives inside of the
travel.
action of the converted firearm. The
floating chamber will perform all of the › Roller delayed – Like its name im-
functions of the cycle of operations for plies, the roller delayed blowback
a semi-automatic action while utilizing system relies on “rollers” to slow the
the controls and ergonomics of the host bolt’s movement during discharge.
firearm. Once training is complete, the The system utilizes a multi-piece bolt
floating chamber can be removed and design, with a bolt head, carrier, car-
the original caliber bolt can be replaced. rier extension (wedge), and rollers.
This allows the operator to practice the When the chamber is closed, the bolt
manual of arms for the given firearm, head and carrier will compress into
while using low cost ammunition. each other, causing the carrier exten-
sion to drive the rollers into recesses
• Delayed Blowback – The delayed blow-
in the receiver.
back system works in a similar manner
to the straight blowback action, but uses Like other blowback actions, during
an additional system to help hold the discharge the cartridge case will begin
chamber closed during discharge. The driving the bolt head rearward. The
delayed blowback system was devel- bolt head instantly begins forcing the
oped so that more powerful cartridges rollers back. The rollers, being limited
could be used with the simplicity of the in movement by the receiver, begin to
Figure 5a: Roller delayed blowback action.
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