Mma Machine Gun Tripod Mount And Traversing And Elevating Mechanism Maintenance Instructions cont

REASSEMBLY

1 Place mount pintle (7) (M122 only) in sleeve bushing (8) and lock pintle lock assembly (10).

2 Place traversing and elevating mechanism (1) on traverse bar assembly (9) and secure by turning traversing lever (2) clockwise.

3 Place flex mount (6) (M122A1 only) in sleeve bushing (8) and on mechanism assembly (5) and lock pintle lock assembly (10).

4. Install pin (4) and replace retaining clip (3).

M249 Machine Gun

THIS TASK COVERS:

a. Disassembly b. Inspection/Repair c. Reassembly

INITIAL SETUP

Tools and Special Tools

Small Arms Repairman Tool Kit (item 2, appx B) Small Arms Shop Set (item 1, appx B)

Materials/Parts

Bolt, machine (5169879) Bolt, machine (2) (5169880) Bolt, machine (2) (5169881) Lockwasher (2) (11010529) Nut, plain, hexagon (4) (MS51968-2) Nut, plain, hexagon (3) (MS51968 8)

Equipment Condition

6-4 Traversing and elevating mechanism and pintle mount/flex mount removed

DISASSEMBLY

Machine Gun Mechanism

1 If damaged, remove two hex plain nuts (1), two machine bolts (2), and two sleeve spacers (3) from head (4).

WARNING

Make sure pintle lock assembly is in locked position before removing.

2 If damaged, remove two machine screws (5), two lockwashers (6), and pintle lock assembly (7) from head (4). Discard two lockwashers.

3 Remove two hex plain nuts (8), two machine bolts (9), and traverse bar assembly (10) from pintle tripod mount legs (11 and 12).

4 Remove two hex plain nuts (13), two machine bolts (14), tripod mount legs (11 and 12), from head (4).

Bar Assembly Traversing

WARNING

To avoid injury to eyes, use care when removing and installing spring-loaded parts.

5 Remove straight pin (16), sleeve latch (17), and helical spring (18) from body (15).

6 Remove hex plain nut (19), machine bolt (20), and tripod mount leg (21) from head (4).

7 If damaged, remove setscrew (22) from sleeve bushing (23), and remove sleeve bushing (23) from head (4).

1 Inspect for broken, damaged, or missing parts.

2 Pintle lock assembly is a repairable assembly. Refer to paragraph 6-7.

Tripod Parts Replacement

3 If body (2) is broken or damaged, repair is by replacement of the next higher assembly.

4 Repair is by replacement of authorized parts (appx C). REASSEMBLY

1 If removed, install sleeve bushing (1) in head (2). Install setscrew (3) in sleeve bushing (1).

2 Install helical spring (4), sleeve latch (5), and straight pin (6) on body (7).

3 Install leg (17) and tripod mount leg (12) on head (2) and secure with two machine bolts (20) and two hex plain nuts (10).

4 Install tripod mount leg (11) and secure to head (2) with machine bolt (20) and hex plain nut (13).

NOTE

Adjust hex plain nuts for 0.003 in. (0.008 cm) maximum clearance between head and legs. All legs must pivot freely.

Place legs in vise before staking.

5 Stake hex plain nuts (10 and 13) to machine blots (9 and 12) in three places.

NOTE

Traverse bar assembly (16) must be adjusted so the sleeve (14) and stop (15) are 0.25 to 0.38 in. (0.64 to 0.97 cm) apart before locking.

6 Install traverse bar assembly (16) on two tripod mount legs (12 and 17), and secure with two machine bolts (18) and two hex plain nuts (19).

7 Stake hex plain nuts (19) to machine bolts (18) in three places.

8 Tighten nut (20) and stake in slot on traverse bar assembly (16).

9 If removed, install pintle lock assembly (21), two new lockwashers (22), and two machine screws (23) on head (2).

10 If removed, install two sleeve spacers (24), two machine bolts (25), and two hex plain nuts (26) on head (2).

11 Stake two hex plain nuts (26) to two machine bolts (25) in three places.

Nuts Machine Mags Guns

THIS TASK COVERS:

a. Disassembly b. Inspection/Repair

c. Reassembly

INITIAL SETUP

Tools and Special Tools

Small Arms Repairman Tool Kit (item 2, appx B) Small Arms Shop Set (item 1, appx B) Spanner Wrench (item 3, appx B)

Lockwasher (11010413) Self-locking nut (MS51943-2) Self-locking nut (MS51943-4) Spring pin (MS16562-120)

6-4 Traversing and elevating mechanism disassembly

1 Remove two retaining rings (2) from headless grooved pin (3).

2 Remove headless grooved pin (3) from traversing and elevating mechanism.

3 Remove and discard two self-locking nuts (1 and 5).

4 Remove traversing handwheel (4) as a unit.

WARNING

To avoid injury to eyes, use care when removing and installing spring-loaded parts.

5 Separate union nut (8), scale dial (7), headless straight pin (10), compression helical spring (9), and knob (6).

Nuts Machine Mags Guns

6 Remove woodruff key (14) and flat washer (11 ) from traversing screw (15). Push traversing mechanism ring (13) from yoke (12) and remove traversing screw (15) from yoke.

7 Pull out slightly on elevating stop assembly (18) and remove elevating screw assembly (16) from elevating mechanism sleeve (17).

Tripod Mechanism ElevatingNuts Machine Mags Guns

NOTE

Break staking stop screw with punch and hammer before removing gun stop.

8 Turn elevating screw assembly until compressed or flush. Using spanner wrench (item 3, appx B), remove automatic gun stop (19) from end of elevating screw (20).

Automatic Assembly Screw Gun

9 Remove upper elevating screw (21) with scale plate (22) attached.

10 If damaged, remove scale plate (20).

11 Remove externally threaded ring (24) from lower elevating screw (23).

12 Remove setscrew (26) and lower elevating screw (23) from knob (25).

13 Smooth stake marks on handwheel click ring (28) and remove. Remove dial pointer (27) from knob (25).

WARNING

To avoid injury to eyes, use care when removing and installing spring-loaded parts.

14 Remove headless straight pin (31) and compression helical spring (30) through the center hole of knob (25).

15 If damaged, drill out plain solid disk (29).

16 Drive out and discard spring pin (32).

M122 TripodSpring Loaded Sleeve Gun

17 Smooth staked metal on elevating stop assembly (18) and remove from elevating mechanism sleeve (17).

18 Remove machine screw (37) and lockwasher (36) from traversing lever (35). Remove traversing lever torsion helical spring (34), and machine screw (33) from elevating mechanism sleeve (17). Discard lockwasher (36).

INSPECTION/REPAIR

1 Inspect for broken, damaged, or missing parts.

2 If yoke is broken or missing, repair is by replacement of next higher assembly.

3 If upper elevation screw, lower elevation screw, traversing screw, or elevating mechanism sleeve are broken or damaged, repair is by replacement of next higher assembly.

4 Repair is by replacement of authorized parts (appx C).

NOTE

Machine screw (1) will need to be adjusted when traversing lever is installed. Traversing lever must be aligned with traverse bar assembly.

1 Install machine screw (33), torsion helical spring (34), and traversing lever (35) on elevating mechanism sleeve (17). Secure with new lockwasher (36) and machine screw (37).

Sleeve Gun Mechanism

2 Install elevating stop assembly (18) and stake in four places near bottom. Install new spring pin (32) and stake material of elevating mechanism sleeve (17) over spring pin on both ends.

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