M17/M18 MHS: Rear Sight Inspection and Repair

Dear Editor,

There have been two maintenance messages released about proper inspection and repair of rear sights on each M17/M18 modular handgun system (MHS). Here at TACOM, we’re seeing a trend that these procedures are not being followed.
 
We want to remind Soldiers to check the rear sights on every assigned M17/M18 MHS, regardless of serial number or how long the unit had these pistols in the inventory. If they find an issue, they should notify a 91F immediately.
 
The following procedure must be completed by a 91F and the only authorized Loctite® products for this procedure are:

• Loctite 271 Red, NSN 8030-01-565-0423
• Loctite 243 Blue, NSN 8030-01-620-3313 

 

1. Remove the rear sight, NSN 1005-01-675-9500, and the rear sight screw, NSN 1005-01-665-4524, per WP 0010 in TM 9-1005-470-23&P (Jun 19).
2. Inspect the rear sight screw to see if there’s a red Nylok® patch on the threads of the screw.
3. Thoroughly clean the screw and rear sight threads to remove any existing Nylok® or Loctite®.
4. Apply one drop of Loctite® 243, NSN 8030-01-620-3313, or Loctite® 271, NSN 8030-01-565-0423, to the interior threads of the rear sight.
5. Insert the loaded chamber indicator spring and the loaded chamber indicator into the slide. 

Note:  Perform step 6 for one-piece rear sight installation.

6. Install the rear sight plate assembly onto the slide.

Note:  Perform step 7 for two-piece rear sight installation.

7. Install the rear sight plate and rear sight onto the slide. 

8. Install the screw into the rear sight. Tighten the screw to 21 in-lb.
9. Back the screw out until it is loose but not completely out.
10. Tighten the screw to 34 in-lb.
11. Check the rear sight plate and rear sight to ensure they are not loose.

Using Loctite® 243 or Loctite® 271 allows for reuse of the rear sight screw. The rear sight screw will no longer be a mandatory replacement part (MRP).

Don’t operate the pistol for 24 hours after the procedure is complete to allow for the cure time.
 
We also want to stress that operator PMCS is key in preventing damage. Operators should make sure they check the sights for tightness both before and after firing, along with regular maintenance intervals. This will ensure the sights stay intact and the pistol remains fully mission capable.
 
For more details, grab your CAC and click on the following message numbers MA 21-006 and MA 22-012.

If you have questions, contact me at:
   

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Editor’s note: Great information, Randolph. Units, make sure the 91F has completed the inspection and repair as outlined above. Operators, always check your weapon’s rear sights to make sure they aren’t loose.