Not US guns.
Guns from international trade. Machine guns, sub-machine guns and machine pistols. None of which are practical to deliver from US sources, as the few remaining legal full-automatic weapons available here in the US were either manufactured before 1986, and due to scarcity are enormously expensive, or are not available in commercial channels if manufactured after that date.
Law enforcement and military can obtain the full automatic weapons, but unless somebody is stealing them out of an armory somewhere, or dealing them illegally, there is no way these weapons would be coming from a US source.
I hear ya, I agree with you both. We know Mexico gets grenades from Korea.
Our problem is, the populace will hear Eleanor Clift and her ilk and NO one is going to hear the truth.