5. Check elevation Index 161 and windage knob (71 for legibility of markings Check underside of windage knobs for cracks. Detent indexing surfaces should be well formed.
6. Check rear sight assembly base (81 for serviceability Clear drain holes for springs Threaded portion of rear sight assembly base and elevation knob should be well formed.
7. Inspect rear sight guards for bends, if bent refer to the following page for repair procedures.
8. Inspect all parts for damage and wear Replace all defective parts.
1. To straighten bent rear sight assembly guards (1), remove rear sight assembly components. Place carrying handle (2) In a vise using jaw clamps. Tighten vise to firmly hold upper receiver (3).
2. Using two adjustable wrenches, gradually bend guards (1) to straighten. When bending the guards (1), gradually bend beyond the straight point as the guard will partially return when bending pressure is stopped.
3. After straightening, use a flat file to remove any nicks, kinks, or burrs that remain on the inside of guards (1).
Do not use wire brush on aluminum surfaces
4. Apply solid film lubricant to brightened area for final protective coating.
5. Replace rear sight assembly components and check that rear sight assembly functions properly. If rear sight assembly functions check out, return upper receiver assembly to service.
6. If rear sight guards cannot be straightened utilizing the above procedures, replace the upper receiver d. LUBRICATION
Lubricate upper receiver assembly and rear sight assembly. Apply CLP to helical springs and ball bearings (three each) and threaded portion of screws before installation. Lubricate helical springs and ball bearings through their respective drain holes.
3. Assemble elevation knob (5), elevation index (6), and new index screw (7) using 1 16 Inch alien wrench. Do not overtighten Index screw as scale will require adjustment
4. Install ball bearing (8) and helical spring (9) using needle nose pliers or tweezers
5. Depress ball bearing (8) with a punch Inserted through access hole, and slide elevation knob assembly In upper receiver (3) from the side Center elevation knob assembly
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