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Measuring Velocity with a ProChrono Digital Chronograph

July 28, 2012
Bill Waugaman , Ohio Valley Outdoors

When it comes to the accuracy of any firearm, there are two considerationsthe firearm itself and the ammunition. Even an extremely accurate firearm will not shoot up to its potential if the ammunition isn't a good match. That is why its best to shoot several different brands and loads of ammunition in your firearm to see what performs the best. For those who hand load, they have the ability to test various combinations of powder, bullet, brass and primers to work up the best combination. One of the accuracy parameters to observe is the muzzle velocity, whether it's for hand loads or factory loads. The tool used to measure bullet velocity is a chronograph.

There are quite a few chronographs available and are reasonably priced in the $100 to $200 range. After some research on the internet and talking with some friends, I decided on a ProChrono digital chronograph from Competition Electronics (Rockford, IL) for this article. It's designed and manufactured in the USA, and it can meet the needs for a wide variety of velocity testing. The ProChrono can be used with rifles, pistols, shotguns, paintball guns, airsoft guns, bb guns, pellet guns, crossbows, compound and recurve bows.

How the ProChrono Works: The ProChrono is about 16" long, 4" wide and 3.25" tall. There are two slots about 4" wide on the top and about 12" apart, each with a special sensor that detects changes in light intensity. When an object such as a bullet passes over the sensors, the light rays are interrupted. By measuring the time between the two sensors being interrupted, the velocity is calculated.

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The Operating Instructions manual is very nicely done, easy to read and has a variety of tips on how to get the best performance for the velocity you are trying to measure. For example, the distance from the front sensor is important. For arrows you should be a little more than 1 arrow length away; for pistols, 5' to 10' away because of light from the muzzle blast; for paintball, BB and pellet guns, muzzle distance is not a factor.

Other Features of the ProChrono:

* The ProChrono works best on overcast, cloudy days. If it's bright and sunny, the ProChrono comes with light diffusers that mounts above each sensor.

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* There is a standard 1/4x20 screw mount in the bottom so the Prochrono can be mounted on a tripod or lay on a flat surface. At just over 2 pounds, it doesn't require much support, but it needs to be stable.

* Velocities can be measured anywhere from 21 to 7,000 feet/sec (or in equivalent meters/sec).

* The stated accuracy is +/- 1% or better of the measured velocity.

* The minimum time between shots is 250 millisec to 500 millisec (that's equivalent to the time between two shots of a firearm capable of 120 to 240 rounds/min).

* The operating temperature range for the ProChrono is 32F - 100F.

* Except for the on/off switch on the side, 5 buttons on the front panel control all of the functions (delete shot, delete string, redisplay, string change, review) that show in the 1/2" LED display. Power is supplied by one 9V alkaline battery (not included).

* For review, the internal memory can store up to 9 strings of shots and each string can be up to 99 shots.

Competition Electronics offers a variety of optional accessories for the ProChrono. You can get a USB remote control, indoor lighting kit, debris shield, digital remote control and portable IR thermal printer.

The ProChrono chronograph has an MSRP of $119.95 and comes with a 2 year warranty from date of purchase for the original owner.



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