FM 23-45 Basic Field Manual
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shoulder does not strike and bur the edge of chamber. Strike forward on bolt handle to
be sure that ruptured cartridge extractor is seated in ruptured case. Pull bolt to the
rear and catch ruptured cartridge extractor in the left hand as it is ejected.
2. To use the Mk. IV, draw bolt handle to the rear and latch it. Insert nose of
ruptured cartridge extractor in chamber, handle up, push it forward to seat it firmly in
the separated case, then pull backward on handle.
(b) Separated cases should be removed from the ruptured cartridge extractor so
that it will again be ready for use. To do this, the end of the ruptured cartridge
extractor must be unscrewed, the separated case taken off, and the end screwed on
again.
(2) The use of the combination tool facilitates the removal of a round which is
stuck on the T-slot. To remove a round from the T-slot, pull bolt fully to the rear and
raise extractor. If the round does not fall out, remove it with the combination tool. If
the round is above the bolt handle slot, insert screw driver end of tool through slot and
under the rear end of cartridge and pry it up. If the round is below the slot, place screw
driver end of tool through top of receiver into cannelure of cartridge and drive it down.
(3) The cleaning rod is used to remove a case from the chamber which has not
been extracted by the bolt. To remove the case from the chamber, pull bolt fully to the
rear and hold it. Remove the following round from the T-slot. Grasp cleaning rod about
6 inches from the end, insert it into muzzle, and force case from chamber. Care should
be used not to damage the face of the bolt by striking it as the rod is shoved through
the bore.
d. Inspection of feed mechanism.—In event of recurrent or permanent failure to feed,
the feed mechanism must be inspected and the defective part replaced. This inspection
should include the following:
(1) Belt feed lever and slide.—
(a) With the bolt forward, lower cover, making sure that stud on feed lever is in
cam groove in the top of bolt.
(b)Press to the left on heft feed slide to remove the play and note whether or not
the slide protrudes to the right of the cover about 1/32 inch.
1. If it does not, change belt feed lever and pivot.
2. If it does, and the gun has occasionally failed to feed, examine belt feed
lever for excessive wear at the pivot and stud. Also see that stud projects a sufficient
distance from cover to insure that it is positively positioned in cam groove in the top of
bolt when cover is closed. Replace defective parts.
(2) Other parts.—If the slide positions properly and no excessive play exists,
examine cover extractor spring; belt feed pawl, spring, and pin; belt holding pawl and
spring; extractor including ejector; spring and cam plunger; and T-slot, to see that
these parts are there, in good condition, and that springs are sufficiently strong to
actuate the parts properly.
■42. IMMEDIATE ACTION.—
a
. General.—The procedure prescribed in immediate action for the reduction of
stoppages is based on the frequency with which the various types of stoppages occur.
Execution of this procedure by the gunner will enable him to remedy the majority of
