Drop-in triggers on a Polymer80 frame: what fits and what does not

A Polymer80 pistol frame uses the Gen 3 Glock fire control layout, so most aftermarket Glock triggers install without modification. Most, not all. Here is what to check before you buy.

Generation first

Buy a trigger described as Gen 3, or Gen 3 and 4 compatible. Gen 5 triggers use a different trigger bar geometry and a relocated ejector, and they do not work in a PF940-series frame.

Frame size second

Full-size and compact frames share a trigger bar length; the subcompact PF940SC and the single-stack PF9SS use their own shorter bars. A G19 trigger assembly will not run correctly in a PF9SS.

What a drop-in kit includes

Usually the trigger shoe, trigger bar and connector, sometimes the springs. It rarely includes the trigger housing, so keep the one from your lower parts kit. If the kit supplies its own connector, do not mix it with the factory one.

The two fit problems people hit

First, a trigger bar that drags on the frame rail because a rail tab was left proud during finishing; file the tab, not the bar. Second, a connector angle that gives a light wall but an unreliable reset. Check reset by hand twenty times before the range.

Safety check every time

After any trigger change, function check the completed pistol unloaded: trigger pull, reset, drop safety plunger movement, and that the striker does not release when the trigger is not pressed. If any of those fail, stop and recheck the install.

AR triggers

The RL556v3 and G150 accept any mil-spec AR-15 trigger group, including drop-in cassettes, once the fire-control pocket is finished to the jig line. A pocket cut short is the usual reason a cassette will not seat.

This is general information, not legal advice. Laws on unfinished frames and receivers vary by state and city and change often. Check the current law where you live before ordering.