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Did My Chrony Eat Mushrooms? July 2023
Gerhard Schroeder  

An optimistic result. Old sabot strike damage is apparent.

As reloaders we like to know how fast our bullets come out the barrel. Once chronographs became affordable and apparently functional, it did not take long before a CHRONY F-1, their cheapest version, also came out to the range with me, occasionally. The darn thing is a little bit of a pain. That’s primarily because its functionality is sensitive, as a minimum to position, to sunlight. When all is well, we get the rewards in feet per second. At least most of the time. However, may we not be too naïve, because sometimes the number on the display appears just a little too good to be true. At least on my CHRONYs it did.

Yes, CHRONYs. I’m on number 2. Murdered the first one, I did. Not out of hatred. It was 2nd degree, when while firing my small Kahr 9mm offhand across the screens one shot came in too low. It was instantly fatal. Number 2 has the same sensitivities. I don’t even try until the sun is on it. Even then the “ERR1” message appears frustratingly often. OK, nothing personal, but I do seem a little harsh on these measuring devices. Because about 4 years ago I smacked Nr2 with a sabot that had separated from a .308 Win load firing a 22cal bullet. That sabot impacted the edge of the screen, but apparently did not affect function.

Then in late March 2023 an opportunity showed up. Buddy Jim from CA came to visit, brought his 6.5 Creedmoor to try at distant targets, ranges not available near his home. Oh yes, when shooting at longer distances knowing the exact muzzle velocity is indeed very helpful. For that he brought his device, a ProChrono. We set that up in the proper place, then set up my CHRONY directly behind it. When he fired 129gr Hornady bullets, his ProChrono gave appropriate readings in the 2600 fps range. My CHRONY showed something around 1200 fps, what I call stupid data. It happens. As the morning went on and the sun climbed, the CHRONY awoke. But then each time it read about 50 to 70 fps less than the ProChrono. At that point I was ready to kill my CHRONY #2 also. No 9mm was at hand to make it look like an accident. That was good. Because later it became obvious that it was silly of me to expect dependable and repeatable results from the type of chronograph that uses optical changes to capture bullet speed. Testing continued. I fired my .260 Rem. with Hornady 140gr ELD-M bullets next. Now CHRONY and ProChrono read within 10 fps of each other. Huh? Which one can be trusted, if any?? I kept the CHRONY for the time being. At least it should provide ballpark info.

Shortly after, I engaged in a Redhawk .44 Mag evaluation. There came strings of data like 1065; 1056; 1065; 1254; 1039. Or 1000; 1445; 1076. I was convinced my ammo was not that inconsistent, ignored the misfit readouts. Then came the optimistic result seen above. And later also 3984. My CHRONY was apparently “high” on something. Now I wish these speeds were real.

OK, maybe not. Can you imagine the recoil from a 240 grainer out of a revolver at those velocities? I had enough, ordered a ProChrono that same afternoon. That may have been a tad too emotional, too early.

Before my ProChrono arrived, another thought trickled in. Why not a further comparison test in series with the CHRONY Master and MagnetoSpeed which reside in Steve’s possession. He agreed. Here is the test setup →

Note the weight below the tripod to help avoid sudden winds from blowing the setup down. That’s from experience.

First Steve shot his 26” R700 in .260 Rem, Berger bullets, with two different powders. The data we gathered appears a little sobering. For his first 5 shots agreement between the three devices varied from 2 to 40 fps. And one of the CHRONYs always indicated a faster speed than the Magnetospeed, just not always the same CHRONY. Also no surprise that CHRONY F-1 had 2 stupid readings. For his next 5 shots the agreement worsened, ranging between 3 and 52 fps. You can see all data in the table below.

Then Steve attached his Magnetospeed to my Tikka CTR, also in .260 Rem, firing Hornady 140 gr. ELD-Ms. Agreement improved, from 1 to 13 fps between the 3 devices. Now such results I could live with. Since I had it along, my TC in 30 Herrett also got a quick go, but without the Magneto. The CHRONY Master had trouble with those 110 gr. Vmax bullets, giving us 4 out of 6 stupid readings. And are the CHRONY F-1 results real??

Some conclusions:

The CHRONY Master displayed the highest speed most of the time. Best, but by no means consistent agreement was between the CHRONY Master and MagnetoSpeed. Worst agreement was between the two CHRONYs.

All 3 had better agreement with the Hornady 140 gr. ELD-M bullet than the Sierra 130 gr. Tipped Game King.

Five days later we were at it again. Now there were 4 measuring devices! Dan assisted by adding his LabRadar to the test setup. Of the four devices, the LabRadar was by far the easiest and fastest to set up. Also, by sitting 18” to the side of the barrel, there was no functional interference from the two CHRONYs and their sky screens and support rods. Plus, the unit was completely out of harm’s way.

Note that the test and setup took place in the same location, same time in the morning, same target position, meaning basically very similar sunlight conditions.

First Steve tested two loads in his Tikka CTR in .260 Rem. Then my CTR in .260 Rem got on the bench, firing 4 different loads. After that my Tikka T3 in .223 Rem provided a data string. All of that is summarized in the second table, below.


No erroneous (or stupid) readings occurred that morning. The CHRONO Master recorded the highest speed for each of the 35 shots. Worst agreement of the measuring devices was between the two CHRONYs, best between MagnetoSpeed and Labradar. Similarly, the agreement between MagnetoSpeed and CHRONY F-1 can be called “good”. But that was for this day, this test. The previous testing with (only) three devices did not reflect such good agreement.

Clearly though, the Labradar is a winner. Easiest to set up, and able to measure bullet speed from any gun. The MagnetoSpeed is also independent of light conditions, but will not work with a suppressor and most, if not all, handguns. Its attachment method is somewhat Mickey Mouse, and will that interfere with the accuracy of a longer thinner barrel? It holds true here as well: you get what you pay for.

Well, since it arrived, a few words about my new Pro Chrono. Yes, it is light sensitive. To date, though, it has given believable readings well before sunlight hit it. I am not sorry about that purchase.

In its literature they recommended ‘side shields’, to make the ambient light at the sensors as consistent as possible. I made some, which was easy to do, and no big deal to install each time. Now, many outings later, I’d say that the Pro Chrono sets up easier than the Chrony, is sturdier. Its increased length also makes it easier to align with the target, such that speed and accuracy get tested simultaneously. Which really means that I get a reading on the first shot of the morning. That was at best 50-50 with the Chrony. We did not run any more comparison tests. I like that Pro Chrono, will simply ‘take’ what it tells me from now on – except for obvious stupid readings, of which there have been very few in several hundred shots fired to date.

These days, with components often not available, and always expensive, I wish I would have troubled myself in the past and set up that Chrony each time, and then recorded all data. The Pro Chrono will see such employment.

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