The design of the Urutau is inspired by previously published 3D-printable firearm designs, the
Derwood Shuty, the
FGC-9 by JStark1809, and the Partisan 9 by . With the exception of fasteners, pins, springs, and other widely available metal hardware, the rest of the Urutau is 3D-printed. • A bolt carrier assembly which uses an M8 screw to secure the metal components to the plastic instead of using adhesives. This modification is intended to optionally enhance the ease of disassembly at the expense of a little more work up front. • This modification was made standard in the v1.1 update to the Urutau, however it uses an M6 screw instead of an M8 screw. With the update, adhesives are no longer recommended to complete the bolt carrier assembly. Some of these modifications include modified grips and barrel covers. First, he noted that the select-fire design was unreliable given an issue with bolt-bounce and
auto sear timing. Second, he noted that they were unable to test the select-fire design to
Deterrence Dispensed standards. Lastly, he noted that the documentation's author, RSmith28, refused to write documentation for a select-fire design due to
International Traffic in Arms Regulations (ITAR) concerns. As of the Urutau's publication, technical data for non-automatic and
semi-automatic firearms were removed from the
United States Munitions List (USML), the list of items controlled under ITAR, but fully automatic firearms and conversion devices thereof had not. On June 12, 2025, Zé Carioca announced that "No more blown primers or bolt bounce! All issues with the select-fire version [of the Urutau] are resolved, with release expected in 60-90 days." The announcement included a video of an Urutau firing in full auto without any issues. == Documentation ==