While the AR-15 lower receiver is frequently printed, the upper has long been a dream of firearms printers. In Carbonite very well may have produced the first working AR-15 .22 caliber upper receiver.

When I first printed it I had no idea if it would work, so I was glad to find out that it did. The first one broke after several trips to the range at a total of about 450 rounds. The point of failure was the holes for the takedown pins.

" I printed this on an anycubic i3 mega 3D printer which cost about $300 I used PETG filament for the upper, but I believe PLA would work just as well."

" I decided to change the orientation I print the upper on the printer to strengthen that area, so I printed it vertical. That fixed the problem, and I have since printed another for use in a rifle platform (still .22lr)"