Isn't home gunsmithing legal in the US? Also the luty sub gun is typically less reliable than 3d printed guns, so maybe go that route. a shooter in germany like 2 years ago made a luty and he made just as much destruction with a slam fire pipe shotgun, he was a total fuck up though, couldn't get into a temple so shot a random german woman and killed a kebab shop worker, a sand nigger yes but a working sand nigger who had been in the country for like 20 years.