The ProChrono Digital chronograph

The shooter’s best friend

Gordon Hutchinson

July 21 at 9:00 am  | Mobile Reader | Pring this storyPrint 

It once was expensive and cumbersome to test rifle ballistics, but the digital age has made the use of chronographs very affordable.
Gordon Hutchinson
It once was expensive and cumbersome to test rifle ballistics, but the digital age has made the use of chronographs very affordable.

I’ve written about the “wildcatting” era in the early 1950s when the U.S. economy was booming in the years coming out of World War II and then the Korean War. 

The shooting business was also booming, and shooters were experimenting with loads of powder, weights and designs of bullets. “Wildcats” were bullets developed by shooters trying to better existing calibers and loads.

It was an amazing time, and a lot of cartridges invented in home reloading shops and local gunsmith stores gained in popularity, and were standardized and brought out by major bullet manufacturers.

The guy that encouraged my interest in shooting was my personal hero — my mother’s brother, Leonard M. “Buzz” Williams.

Buzz was a chemical engineer who graduated LSU and worked on fuel designs during the war at the old Esso Refinery in Baton Rouge. His job was sensitive, so he was draft-deferred. 

After the war, he and other engineer buddies started a gunsmith shop on the side, mainly to work on their own guns and to get a federal firearms license so they could buy guns and parts at wholesale prices.

But then and now, if you were going to do any sort of serious cartridge testing and design, you had to have a chronograph — it was only through these instruments could you tell how fast your bullets were going — and chronographs were expensive.

In fact, it was rare to see a chronograph outside a company lab or shooting range. They were just too expensive for individual use — and they were bulky, hard to pack up and carry to the range.

So Buzz and his engineer buddies worked up a common instrument for the times: a “ballistic pendulum.”

This contrivance allowed you to shoot a bullet at a pendulum device. Knowing the weight of the pendulum and the bullet, and measuring the movement of the pendulum would allow you to figure the velocity of the bullet.

Ken Oehler revolutionized the chronograph business by bringing out the first true portable chronographs that shooters could carry to the range — and while more in line with most shooters’ budgets, they were still sort of a luxury item — a bit pricey for most shooters. And the early ones used three skyscreens, had wires to run the information from the screens to the computer/printer, and needed tripods or other support methods to be used effectively.

I had one of these early Oehlers, a Model 35P — and while it was the sine que non of experts in its day, the trappings prohibited a quick trip to the range to test loads. You had to set up the screens on a tripod or other support system, then set up the three sky screens to shoot through. It worked and it was extremely accurate, but it was more of a hassle to set up than one wanted in a quick shooting trip.

Thank God for the digital age. Chronographs now are so small, portable, and accurate that they can be carried in shooting boxes to the range, set up in just minutes and record shots in practically any light conditions.

One of the highest-rated designs is the Pro Chrono Digital. The wonder of the Internet lets you compare other user experiences, and this model by Competition Electronics consistently gets great reviews by users.

I liked its portability, light weight and ease of setup.

Unlike some models, the diffusers are made from sturdy, flexible molded plastic material. Some models have thin, stiff diffusers that are jointed and have to be snapped together before setting up on the support wires — and are easily damaged or broken.

The Pro Chrono Digital diffusers withstand about any misuse short of shooting them (and boy, will you feel foolish then). With a single 9-volt battery installed, the whole machine weighs just a couple of ounces over 2 pounds.

While it seems contradictory, chronographs work better on cloudy days; the diffusers or skyscreens are for sunny days.

From the manual, we get an excellent explanation of the way these instruments operate: “The ProChrono Digital chronograph operates on the principle of measuring the time it takes for an object to travel from the first projectile sensor to the second projectile sensor. The sensors, mounted internally in the case, gather light through the two rectangular openings in the top of the case.”

This is a quality chronograph that is simple to set up and use. Just remember to set it far enough from the muzzle to keep it from being damaged by the muzzle blast. Years ago I watched a guy set a chronograph at the range, placing it about 6 feet from the end of his centerfire rifle; the blast blew the skyscreens off the machine and the machine off the support box — destroying it in the process.

ProChrono Digital recommends 6 to 10 feet for handguns and 10 to 15 feet for centerfire rifles.

While I am interested only in quick testing of the speed of my loads, this is a surprisingly versatile machine that will allow you to read velocities of projectiles from 21 to 7,000 feet per second. It will also give you high velocity, low velocity, average velocity, extreme spread and standard deviation. Also offered as accessories are a digital remote control and a portable IR thermal printer.

But again, the beauty of this instrument is in its simplicity, ease of setup and extreme portability.

In my first use, I set it up in about two minutes and shot my Remington Guide Rifle in .300 Short Action Ultra Magnum (Remington’s answer to the .300 WSM) through its target area. I was pleased to discover the 150-grain bullet was traveling just about where the box said it should be — between 3,100 and 3,200 fps.

Several shots through the screens proved the factory specs were accurate — and that the short magnum was living up to its promise of magnum velocities out of a shorter action and barrel.

This is a versatile, accurate and handy machine — easily carried to the range to test a wide variety of projectiles from air rifles, arrows and crossbow bolts to your shotgun and centerfire rifle loads.

A quick check on the Internet showed prices running $100 to $120 and consistently highly rated reviews of performance.

At those prices, how can you miss? 




View other articles written Gordon Hutchinson