I like the AMC Rebel Machine, too, but the SC/Rambler is just over the top cool. Notice the red, white and blue stripes in the grill. AMC was never bashful at being BOLD!
It is not an explosion from the type of round it is. That is cavitational force collapsing in on itself at supersonic speed which creates enough pressure to create the flash of light or energy you see there. Watch this for an example of what is happening, but what you see there is what makes bullets like the 5.56 deadly. That is what happens inside your body when certain rounds pass through you, and it is usually what does the most lethal damage to the body.