Glacial Wanderer demonstrates how to build a high-speed air gap flash fast enough to capture a speeding bullet without it getting blurred. These types of flash units usually run around $8K+, but for a few hundred dollars you can build you own and capture sick stuff like...
...glass rods being demolished:
or balloons being pierced:
or a bullet coming head to head with a brass rod:
(Above all, be warned: "The provided information is for educational purposes only. Do not build one! If you go against my advice and do build one, I am not responsible for any injury, death, or any other problems it causes.")
*PS, Note the differences in flash speed below: