PETG vs PLA for 3D Printed Guns and Gun Parts (Why my 3D Printed Mac 11 Frame Failed)


Gunny McGunsmith


Published on Feb 23, 2020

During my recent trips to the range, the Mac 11 started having issues with the fire control group. Initially, we had binary firing, but as I tested more and swapped fire control groups, the issue just got worse. Eventually, we had a completely dead trigger, and upon closer inspection it seemed our trigger and hammer pin holes had deformed and "walked" away from each other.

And, before I forget, these failures did occur after firing +p+ (which kicked HARD in this design. There's a not insignificant chance that PETG frames will work A Okay with non +p and +p+ rounds. But regardless, I chose to print a new frame out of PLA which we will subject to the same testing conditions, including +P+ rounds and we'll see if it fares any better.

Given the properties of PLA vs PETG and the testing done by others in the beta, I suspect that it'll be just fine, but AFAIK nobody has pushed this design to large round counts yet (another reason it's still beta). If this frame works, I hope to get to 1K rounds soon on this build and as always I'll keep you guys posted on the progress!