[Grind]

Ok. I'm not going to come up with anything fancy. No logical resoning, no sources to back up my info. But I'm going to tell you how this gun could shoot 600 bullets per second.

know ABSOLUTELY NOTHING about the future. I'll explain how the gun can work.

The gun (though it looks like a regular assault rifle) has 100 different tiny barrels inside the one main barrel. These barrels all shoot at the same time, each one basically it's own seperate AR that all shoot with the push of the main trigger. Now these bullets are obviously very small, and they wouldn't do much damage. But that's fixed because they are exploding bullets. These bullets explode on impact and do a bit less damage than regular bullets. How do the bullets explode? awesome futeristic technology thats how. The gun has insane recoil and can only be shot in short bursts by the toughest of soldiers.

Or maybe like this.

This AR has only one barrel, one normal sized clip (whatever that may be). The bullets inside the clip start out in a gas form, each one the size of 1/100 of an atom. As the tiny particles move into the gun they form into regular bullets and are fired. The AR shoots at 600 bullets per second due to super futeristic technology that allows for a seemingly impossible (but now thanks to super futer technology it is possible) firing rate.