106 American Shooting Journal // August 2019
Step 19:
Install subframe lock. When correctly installed it will interact with the lower arm of the sear spring and will be spring-loaded
in closed position.Step 20:
Install mag bottom catch
and trigger. Using a small
hook tool, install trigger
spring and, lifting its front
tail up, slide it over mag
bottom top until it falls into
spring retention slot.Step 21:
Install locking block on the upper. Make sure that locking lugs sit correctly on the bolt locking lugs.