Heckler&Koch MR556A1 - Manual (Page 19)

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d. Insert the small tip of the disassembly tool into the spring loaded detent located in
the center of the rear takedown pin. While pushing on the disassembly tool, drift the
takedown pin from right to left until the takedown pin reaches its limit of lateral travel.
The tip of the takedown pin should be visible on the left hand side of the lower receiver
(Fig. 66).
Fig. 65 – Closing Upper and Lower Receiver
e. Insert the small tip of the disassembly tool into the spring loaded detent located in the
center of the front pivot pin. While pushing on the disassembly tool, drift the pivot pin
from right to left until the pivot pin reaches its limit of lateral travel. The tip of the pivot
pin should be visible on the left hand side of the lower receiver.
Fig. 66– Detail of the rear Takedown Pin showing spring loaded detent.
f. Install the disassembly tool into the storage channel located at the back of the
buttstock.
g. Mount the recoil pad onto the back of the buttstock with the recoil pad perpendicular
to the buttstock. Ensure that the recoil pad is flush with the buttstock and rotate the
recoil pad clockwise one quarter turn until the recoil pad engages the locking surfaces
located on both the top and bottom of the buttstock.
FUNCTION CHECK
WARNING: Always ensure the MR556A1 is unloaded prior to attempting to perform
a function check.
NOTE: The MR556A1’s selector lever can be placed on safe regardless of the position
of the hammer. Legacy AR15/M16 platforms require that the hammer be cocked prior
to attempting to place the firearm on “SAFE”.
FUNCTION CHECK PROCEDURE
1. Perform clearing procedure (see above) and ensure selector lever is set on “Safe”.
2. Place the muzzle in a safe direction and rack the bolt to the rear three or four times
in quick succession by using the charging handle. The bolt should not bind when
traveling back and forth in the receiver.
3. “SAFE”: Let the bolt go forward and completely go into battery. With an unloaded
MR556A1 and the muzzle in a safe direction, ensure the selector lever is set on
“Safe” and attempt to pull the trigger. The hammer must not fall.
4. “SEMI-AUTOMATIC”: Rotate the selector lever to “Semi-Automatic” (Single Shot)
and with an unloaded MR556A1 and the muzzle in a safe direction, attempt to pull
the trigger and hold to the rear. The hammer must fall.
5. While maintaining pressure on the trigger, rack the bolt and release. The hammer
should be held by the disconnector.
6. Release the trigger. The hammer should be caught by the sear as signified by a
metallic click. Release the trigger completely and re-engage the trigger. Hammer
must fall.
7. Insert an empty magazine into the magazine well and pull back on the charging
handle. The magazine follower should engage the bolt catch and lock the bolt to
the rear on an empty chamber.
8. Remove the magazine and allow the bolt to go into battery, either by depressing the
bolt catch or by pulling the charging handle slightly back towards the rear and then
releasing.
9. Ensure that the MR556A1 is unloaded, place the muzzle in a safe direction and pull
the trigger to ease the tension on the trigger spring.
10. Place the selector lever back on “Safe” and snap the dust cover into position over
the ejection port.