how do chronographs work?
 

thats it how do they work. ive been thinking on it a while ang i cant figure it out. does it measure a shock wave? its not magnetic because most bullets arent made out of a ferrous material. so enlighten me please.

RE: how do chronographs work?
 

As far as I know it works with the equation Distance = Rate times Time (D=R*T). There is a sensor at the front of the crony, and at the back. When the bullet passes the front sensor the crony begins to time how long it takes to reach the back sensor (when the bullet passes the sensors it breaks a light beam.) That number is equal to T or time. The distance between the sensors equals D or distance. The crony plugs these numbers into the equation D/T=R, and figures out the R or velocity for that bullet. I hope this helps. Good luck.

Edited by - handloader1 on 02/14/2002 00:16:35

RE: how do chronographs work?
 

Modern chronys have two light sensors on them at a fixed distance apart. They are activated by the shadow of the bullet crossing them. They have a very accurate clock built into them and the bullet starts the clock when it passes over the first sensor. When it passes over the second light sensor the clock stops. Since the distance between the two sensors is fixed it's a simple matter for the processor to calculate bullet speed by dividing the time for the bullet to travel between the two sensors into the distance between the sensors.

RE: how do chronographs work?
 

i knew it was the simple v=d/t equation for speed but i was wondering how they knew the bullet was passing by and a light beam makes sense. thanks