Shooting Chronograph Assassin

By Patrick Sweeney

“Hello, my name is Patrick, and I am a serial chronograph murderer.” No, not the very spendy chronograph timepiece you wear on your wrist, the shooting chronograph that registers bullet velocity. Name a brand, and I’ve whacked it with one payload or another. Killed ’em all, dead.

A few weeks ago, I was at an LE class where we were demonstrating to the assembled students just how ballistic gelatin works. I had a particular load I wanted to test, so I stepped to the line. A friend of mine wanted to get a photo of the event, but his camera (his phone, actually) couldn’t do high frame rate, so he wanted a countdown. “Three, two, one … .” On zero, I mashed the trigger. You can fill in the rest.

Shooting chronographs work by housing circuitry that generates a very high-frequency vibration. This is used as its clock. The sensors, called skyscreens, note the shadow of a bullet passing overhead. You tell the program in the mystery box how far apart the screens are, it measures the time elapsed between the two shadow-passing events, and it spits out a speed. So far, no problem. The difficulty arises in sensitivity. You see, depending …Read the Rest

Source:: Guns and Ammo