Page 154 - FAT 105 4.17 MOODLE

INTERNAL BOX MAGAZINE FIXED TUBULAR MAGAZINE

The internal box magazine or blind box maga- The fixed tubular magazine gets its name from
zine is a feeding device that lives under the ac- the shape of the magazine body. The tubular
tion of some firearms and is (mostly) fixed in its magazine in its most basic form is just a tube
position. The design gets the name “blind box” with one end capped off. The tube is fixed (either
from the fact that the magazine is not visible screwed or pressed and pinned) to the receiver
from the exterior of the firearm. The maga- with the open end facing the breech. Inside of
zine is only accessible once the action has been the tube is a round follower and coil spring.
locked open. Internal box magazines are fixed in There is another type of tubular magazine that
their capacity (without modification) and typi- is not quite fixed, but not completely removable.
cally hold from 3 to 5 rounds. It is basically a tubular magazine inside of a tube
that is fixed to the receiver. Depending on model
The internal box magazine may feature a hinged
and design, the cartridges may either be loaded
floor plate that will allow the magazine to be
from an opening or window in the receiver or
serviced or unloaded. Some designs require the
through a window in the front of the maga-
operator to manually cycle the action in order
zine tube. The cartridges are arranged in-line
to unload the magazine. Other designs feature a
from tip to base, with the tip (bullet) facing the
magazine cutoff or interrupter, which allows the
muzzle. Inside of the receiver, near the mouth of
operator to stop the magazine from feeding and
the magazine tube, there will be two assemblies
manually feed rounds (such as blanks for gre-
that control the feeding of the cartridges from
nade launchers). The internal box magazine can
the magazine. These parts are known as “stops”
be found in both manual and semi-automatic
and “interrupters.” The stop prevents cartridges
(and automatic) actions, primarily with bolt and
from being forced into the breech prematurely.
semi-automatic rifles.
The interrupter prevents the next cartridge from
While most internal box magazines must be
being released from the tube once the stop has
loaded manually one at a time, some designs em-
been tripped, releasing the first round. Both the
ploy clips or stripper clips. The clip or stripper
stop and the interrupter are activated by the
clip holds multiple rounds (usually 5 – 10) in a
movement of the action, which also controls
thin metal strip or block (en bloc) and fits into a
their timing. The fixed tubular magazine is used
recess in the magazine. The rounds are stripped
with both manual and semi-automatic actions in
from the clip and loaded into the magazine,
both rifles and shotguns. The major advantages
making loading much faster. The clip is removed
of the tubular magazine design are its simplicity
and the firearm can now be chambered and fired.

Figure 2: Internal box or blind magazine. Figure 3: Tubular magazine.

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