Keep the fan speed low to prevent warp.īed Adhesion: gluestick or hairspray recommendedĪll other settings can/should be left as default or whatever you know works best with your printing setup. Infill: 100% Recommended – while the UBAR might not need 100% fill, this ensures that you won’t end up hurting the lower if you overtighten anything.Ĭooling fan: 20% normal, 50% on bridges. Walls: I used 8, but you can use whatever works best for your setup. Recommended print settings for PLA+ were as follows: This receiver should also work in any material similar to or superior to PLA+. The UBAR 3D printed lower AR receiver has been tested to work well in eSun PLA+. If you have a side charging AR, one without a forward assist, or you removed/plugged your forward assist, you can print the no forward assist version, as it will be slightly stronger. Print the forward assist version if you have a forward assist installed on your rifle. Otherwise, the standard lowers will be more robust (since lowering the shelf increases a stress concentration in the lower).įor all the high and low-shelf variants, there are two sub-variants – lowers that have a cutout for the forward assist, and lowers that do not. Print one of the low-shelf models if you use an FRT trigger or other device requiring a low-shelf receiver.

UBAR2 and UBAR2C have four sub-variants: high-shelf options and low-shelf options. Printed Parts Checklist:įour variants are the UBAR2, and four are the UBAR2C – the “C” designation indicates that the lower has a little extra clearance required for some side charging/billet/nonstandard uppers. Using a U-Bolt to reinforce the rear tower and rod end eye bolts to reinforce the front takedown lug, the UBAR is a contender for the strongest printable AR15 lower design at its time of publication. At the core of the UBAR’s design is its simple reinforcements – using hardware store metal parts solves the major design concerns that printed AR15 lowers face.

Glock frame 3d print file