Gun laws will have to change in the USA, its just a matter of how many lives you are willing to lose before they change. None of the following guns have anything in common.
The last gun featured is the Autoplasma released in 2065, its capable of firing plasma bullet 3000 rounds a minute, fitted out in the latest in nano bot release modules no enemy is too big, the nano bots can be programmed to seek and disarm or even bring down a while skyscraper in under 15 minutes. The plasma bullets are a mixture of pure plasma bonded with nanoites, these self targeting and programmable shots detect and seek the target. The bullet will explode on impact or not depending on programming they can explode hitting human flesh and not metal for example. The gun also comes with a self destruct and can be used as a small bomb.