What defines an assault rifle, and why do we need them? You can't purchase a newly made machine gun, so it's not like we as civilians can keep up with the government to prevent a military coup or say an American holocaust. Pretty much any weapon of actual military grade is illegal. You can't purchase hand grenades. To even get a suppressor you have to fill out a ton of paperwork, go through a background check, get put on a list and pay stamp tax. And suppressors only help obscure where the shots are coming from on the battlefield because of all the noise of battle. A surpressed shotgun is still deafening. Literally. You can't take off your ear protection just because you have a silencer. Guns go bang.
So what's the point? If the government decided to arbitrarily haul off and execute people, could we using "assault rifles" fight them off? Be honest with yourself. The Warsaw uprising failed and they had hand grenades and weren't facing drone strikes and soldiers with full body armor and night vision goggles.