Yep...
The strobe is tied to the microphone. when it hears the bang or some other sound it fires the strobe. To get more than one image on a plate you just use a light behind a wheel with slots in it. The shutter on the camera stays open during the entire event.
The bang you hear from a gun is from two sources. The first is the powder going off and the second is the supersonic boom when the round leaves the muzzle. If a round goes more than 1100 feet per second then it's considered supersonic. Not really good for being stealthy. My Colt 45 A1 model 70 fires a .45cal ACP round at 1400FPS. And throws a flame over a foot long. Well that's my Glazer rounds doing all that. The rings you see behind a round caught on film is the shock waves as it passes through the air or ballistic gel. The matrix stuff was a CGI version of this event. Looks cool.
Now see if we didn't have high speed photography you'd never seen all that.