Heckler&Koch MR762A1 - Manual (Page 16)

30 31
5. Lower Receiver:
NOTE: Always ensure the hammer is in the cocked position (down) before attempting
to remove the buffer and action spring.
a. Depress the buffer detent with the tip of the piston rod and remove the buffer and
action spring from the receiver extension (buffer tube) (Fig. 48).
Fig. 48 – Removing Buffer Assembly
b. Check to ensure that the buttstock tightening screw is loose before attempting
to remove the buttstock. If tight, insert the large tip (3mm hex) of the MR762A1
Disassembly Tool into the tightening screw and rotate (but do not completely
remove) counter clockwise (Fig. 49). For cleaning and general maintenance
purposes, it is not necessary to remove the buttstock.
Fig. 49 – Buttstock Tightening Screw
c. To remove the buttstock, simultaneously depress the back of the buttstock release
lever while pulling downwards on the front lip. Slide the buttstock off the receiver
extension.
Fig. 50 – Removing Buttstock
The MR762A1 is now operator disassembled (field stripped).
NOTE: Disassembly beyond the above field stripping procedures should only be
undertaken by HK certified personnel.
REASSEMBLY (ASSEMBLY) OF THE MR762A1
Tools Needed: MR762A1 Disassembly Tool (located in the Buttstock), 5mm Allen Wrench,
Small Straight Slot Screwdriver
1. Lower Receiver:
a. Check to ensure that the buttstock tightening screw is loose before attempting
to install the buttstock. If tight, insert the large tip (3mm hex) of the MR762A1
Disassembly Tool into the tightening screw and rotate (but do not completely remove)
counter clockwise.
b. Two small set screws are located on the bottom of the receiver extension (buffer
tube). These set screws are provided to eliminate any play that may develop
between the buttstock and the extension. The left hand side of the set screw
features a detent surface that engages the buttstock. The right hand surface
features a cut to accommodate a small straight slot screwdriver. Rotating the set
screws clockwise will tighten the detents to the buttstock; rotating the setscrew
counter clockwise will loosen the buttstock. Using a straight slot screwdriver, rotate
the set screws clockwise using quarter turns and adjust until the detents engage the
buttstock but do not hinder removal or installation (Fig. 51)
Fig. 51 – Buttstock reassembly
c. Depress the back of the buttstock release lever allowing the front tab to pivot
downwards. Pull down on the front tab until the locking pin is not visible inside
the buttstock. Mount the buttstock onto the receiver extension. The buttstock is
adjustable for length of pull, with five different settings available to the operator.
WARNING: Ensure that only the proprietary HK buffer and recoil spring (action
spring) are installed in the MR762A1. Use of non HK buffers and recoil springs could
result in cycling problems and affect the reliability of the MR762A1 (Fig. 52).
Fig. 52 – HK MR762A1 Proprietary Buffer Fig. 53 – Installing buffer & action spring