When Soldiers disassemble the MK 19 grenade machine gun, they should make sure after removing the sear plate assembly from the receiver that their priority is putting the sear safety lock on. In the picture below, the safety lock is in place.
Sear plate is locked
Putting the safety lock in place helps to prevent the sear plate from coming apart if it’s accidentally dropped or mishandled. The sear assembly can easily come apart and all the washers inside the assembly can come out and get lost.
The washers are installed in a specific pattern and direction. When Soldiers try to put the washers back in the sear, they typically fail to place them in the right order. This causes the weapon to be out of battery (when the bolt is not in the normal position).
If the washers do accidentally come out of the sear, Soldiers need to let the armorer know so the MK 19 can be sent in for maintenance. The small arms repairers will repair, lube, assemble and then calibrate the sear plate correctly.
Also, here’s a cleaning tip:
While cleaning the MK 19, users should never put the sear plate and the bolt in the solvent tank. The solvent will break down and dissolve the lubricants. Then the weapon will have to be sent to the small arms repairers. They will need to take the sear plate and bolt apart, clean, dry, lube, assemble, and then time and calibrate these two parts to put the weapon back into service.
Fred Fanning II
Ft Leonard Wood, MO
Thanks for the tips, Fred, Mark and David. Operators, follow these tips and save NMC time on your MK 19 machine guns.