This is a little project I've been working on off and on for the better part of two years, maybe more, in between revisions of the BrickAR. it started life as a lower that I found on GrabCad that is long since gone (I've included the original files for that if you want to play around with it). The lower was a two piece design, actually one of the very first ones I ever printed, but I constantly had issues with the replaceable buffer tube section cracking on me at the screw locations. So I said screw it and integrated that back into the rest of the lower and set to beefing it up substantially. I also made some other little modifications to make it compatible with ambi safeties and probably 100 other little tweaks over that time. It doesn't have an integrated trigger guard, but the one I included in the files fits very nicely (I usually don't even pin it in place, just a friction fit). Print it just as it sits, with tree supports from the build plate, and block the pin holes if you want cleanup to be easy. Otherwise, just the same settings that you'd normally use for an AR lower. I've tested it in PLA+ and it works just fine for me, your mileage may vary. Feel free to customize this to your heart's content and share it wherever you'd like, but please don't ask anyone for money for it! I believe that what is freely offered should likewise be freely given.