After a search for and an immediate disappointment with the quality of available models, I saw fit to quickly put together a low-profile autosear for doublestack Glock handguns, such as the G17, G19, and G26. Included in this download are .STEPs and .STLs of both the autosear and a normal backplate.

The way this device works is by automatically depressing the trigger bar, which bypasses the normal semi-auto reset function. To install it, simply replace the backplate on your slide with it. Please keep in mind that this autosear is what you would call a low-profile or "stealth" switch, meaning that there is no toggle for fire mode. When installed, it is full auto and full auto only. And, as you know, the physical object is considered a machine gun under U.S. law, and thus subject to NFA regulation.

This model has been optimized for printing (unlike some existing designs), so please be sure to print with the pointy end facing upwards, and consider using supports for the large overhang. One thing to note is that this can be manufactured via metalworking technique, which will signficantly increase the durability (and therefore the safety) of the autosear.