"This full-scale schlieren image shows the discharge of a .44 Magnum revolver. Two spherical shock waves are seen, one centered about the gun’s muzzle (the muzzle blast) and a second centered on the cylinder. The supersonic bullet is visible at the far left. This weapon produces a bright muzzle flash and a cloud of products of gunpowder combustion that envelops the hands of the shooter. Such high-speed images help forensics experts understand the transfer of gunpowder traces to the hands when firing a gun."
Via Webgard.