Here’s a low budget shooting tip I read on the raindance site –
If you want medium wide shots of bullet holes appearing in the body work of a car try using a slingshot to fire small balls of Blacktack at the doors and sides. The pellets will flatten out into little discs, giving the effect of holes appearing.
Powder off the ball of tack with talc or similar so it doesn’t stick to the slingshot.
Remember, safety first. Do not risk hitting your actors.