Polymer80 Build Guide
A complete walkthrough for building your first Polymer80 pistol — from frame completion to final function check.
Step 1: Frame Completion
Secure your frame in the included jig. Drill the pin holes using the provided drill bits — go slow, let the drill do the work, and clear chips frequently. Remove the four tabs from the fire control cavity using flush cutters, then sand smooth with 220-grit sandpaper.
Step 2: Channel Cleanup
The recoil spring channel needs to be fully cleared and smooth. Use a Dremel with a sanding drum or hand-sand with rolled sandpaper. The channel liner must sit flush — this is the most critical step for reliable cycling.
Step 3: Lower Assembly
Install the locking block, trigger assembly, slide lock, and magazine catch per your lower parts kit instructions. Test the trigger reset by pressing the trigger and manually pushing the cruciform back into position.
Step 4: Slide Assembly
Install the barrel, recoil spring assembly, and all upper parts (firing pin, extractor, spring-loaded bearing, cover plate). Rack the slide multiple times to verify smooth operation.
Step 5: Function Check
With an UNLOADED firearm: verify trigger pull and reset, safety plunger engagement, slide lock function, and magazine insertion/release. Rack the slide 50+ times to break in the components before your first range trip.