English to Spanish Law/Patents Mechanics / Mech Engineering Tools

Hello,

What could be the equivalent of "unrifled/smoothbore" in the following context?


"The Quantum 3D Microscope is based on the new IBIS BULLETTRAX model released in 2019.

Are there separate distributions for conventional rifling, polygonal rifling, and unrifled/smoothbore?
Different models must be developed for each of these rifling types because bullets are marked very differently, and match and non-match distributions will likely be significantly different."