It is a slang for any type of firearm that is automatic (can fire multiple bullets in a fraction of a second) these guns mostly resemble the sound of an AK47
When you postsomething insanely stupid, unintelligent, ignorant, brainless, foolish, dense, moronic, idiotic and everyone laughs at you. Usually accompanied by doing damage control and doubling down.
did you see how he couldn'tread nutrition facts labels properly? that was a certified drac moment!