Home Forums Hunting & Shooting Ask The Gunwriters Do Chorongraphs Lie?

I was at the range today, using a Master Chrony that I have had for a few years. New rifle, a Sako 85 with a 22.4" barrel 270 Win. By the load in the new Hornady book it should have been around 3000fps. I was getting 3370fps with a high of 3405fps.. It was not a Max load either. On another rifle at the same range, same setup, I was getting readings 150fps low from what Hornady said was expected. Can I trust what I am reading? Is there an easy way to check a Chronograph? I suppose I could shoot some standard velocity 22LR and see what it reads. Wondering if it is time for a new one.. Readings were consistent, no wild swings.

Ambient light differences can cause that since we are dealing with bullet’s shadows activating the mechanisms.

I’ve noticed those differences many times shooting the same rifle, load, etc on the same shooting range. The only difference being readings taken one day and then the next.

I had the screens up, and it was a normal mostly sunny day. Will shoot the same loads again next weekend and see if things change. Will also shoot some 1080fps SV 22's and see what it says.

Best reading on an overcast day. Sunny is not very accurate on my Chrony.I always take a 22 along and run a few rounds thru it to see what it is reading

Exactly, over cast or properly shaded will give the most accurate readings.

I've tried a bunch of different light-screen chronographs, though by no means all. Have found Shooting Chronys by far the most sensitive to changing light conditions.

Right now have five chronographs (or is it six?). Have checked the less expensive models against an Oehler 35P and a Magnetospeed, and the most consistent inexpensive brand I've tested is the ProChrono.

JB,
Thank you for the info. I will check it again next weekend and if it still reads somewhat funny I will look at a new one. It has always been consistent, with readings in the ball park. This time I am not sure.. Be nice if those were accurate, but there is no free lunch. Looking at a Labradar, as they are much easier to set up at the range.

I also have the master chrony and I have had good luck and a lot fun with mine, checked it with others and it was right on, I do have to say as others have I pick my days when I use it !!!

Spot on!

Some clouds, but mostly sunny. A total of a 10 shot string with time in between for a cool down. All of them were shall we say were a bit higher than I expected.

In some of the models it's possible for the screens to creep closer to one another.

That always give a very high reading for velocity because the time is the same, but the distance is less. So if the calculation is velocity measures over (as an example) 12 inches, but it's reading over 10 inches the machine thinks the bullet is a lot faster.

I did that once shooting a 44 mag with a 4" barrel and was astounded when my chrono said I was getting 2200+ FPS with a 320 grain bullet. But I found my "eyes" had moved about 1/2 way up the rail, so instead of 12 inches it was crossing only about 7 inches.

If your chronograph has fixed "eyes" I don't know what it is.

But if the yours can move I am betting that's what happened.

I've had accurate results from 3 Shooting Chronys, sometimes for several years--but eventually they all went kinda crazy. I saw it happen with others at the local range too, and never could figure out why. It couldn't be traced to anything simple, like run-down batteries. Eventually I gave up.

I’ve seen a lot of them shot....I’m starting to wonder if it was on purpose.

Have a ProChrono and it works beautifully. However I just bought a Labradar and love the convenience of just pointing it at the target and banging away.

I t was not that expensive, I tend to be cheap. It has worked well to my knowledge so far. The screens are fixed as are the reading elements. Will see what it reads next weekend. I Have a birthday coming up so.. Will clean the lens as well.

Several years I bought one of the Chrony's which seemed to work pretty well until it didn't. Somehow it got shot 9 times while checking velocity of a 9mm pistol.. After that I got an Oehler 35 which works very well and since then a Labradar which is handier and works very well. In the end it seems that to get one of the better chronographs saves many questions.

I'm "pretty sure" mine is almost 150fps "slower" than it should be!!!

They're not like scales, there's no way to check them. Several years ago we put 5 different chronos end to end out of curiosity. Firing (pistols) through them we got what we expected, five different speeds with a huge spread across them. No way to know who's was right of course. Many were there to check loads before a big match, so this caused more questions than answers for some, ending up with some guys bumping up their loads just to be sure, not certain who's numbers to believe.

All joking aside, I check mine with the same box of .22 magnum ammo out of an old Marlin 783. I "know" it is going right at 1920fps. This is on three different Chronys. I keep that same box put away and check my chronograph when I suspect its not reading right. I also change the battery often.

Would have been happy with the 300fps higher LOL. First time I saw a really big swing. The 150fps low was not that long ago. Thinking it has worked till it doesn't.

I had a Shooting Chrony that I KNOW hadn't slept with the number of porn stars it claimed. SOB used to brag night and day.