Talon Sei, a dude on YouTube who is into guns and runs a vlog called “Stuff and Things” gives the Polymer 80 Glock 19 lower build a shot and completes one in a day.
Using a drill press, a box cutter, some sandpaper and a Dremel for clean-up, he hardly even gets his hoodie dirty before tapping in (see what we did) a punch set to add rails and fit an aftermarket G19 Gen 3 slide with an internals kit and sights already installed.
Then comes the internals for the lower and BOOM– you got a homebuilt 9 milly that chews through 15 rounds without a hitch.
Afterthoughts on the build in a separate video below after about 140 rounds. (He gets to the gun at the 5~ minute mark)