Home Forums Hunting & Shooting Ask The Gunwriters Chronographs

The two main benefits of the Oehler are the ability to control accuracy and verification of every shot.

Controlling accuracy - Longer screen spacings are more accurate. Velocity is measuring time to travel a distance. If that distance is small, errors are magnified. In other words, if your measurement of the distance is off 1/8" it is more problematic on a 12" spacing than it is on a 120" spacing. Also, "Seeing" a bullet is difficult. Does the sensor see the nose, midpoint or tail? Does each sensor see the same part? If you have a short spacing and the first screen triggers on the tip of a long bullet but the last screen triggers on the base you will get an inaccurate reading.

Verification of every shot - The Oehler actually makes two measurements of every shot. They are expected to be very close. If they are not close, you know you have a problem. It is like running two chronographs.

The "Song and Dance" involved is that you have to position the screens in front of the gun and then shoot thru them. It is not difficult. It is even easier if you set the firearm on sandbags, pointed at the target, and use a laser boresighter to project a beam forward. You can then align the screens quite easily.

Longer screen spacings make it a bit more difficult but still doable. If you go over about 8', you probably need support for the middle screen as well as the two end screens.

I usually test with a 9' spacing.

I've said it before: We hear a lot of people say they verify their chronograph by comparing it to an Oehler. I've never heard anyone say they verified their Oehler by comparing it to another brand of chronograph.

All chronographs can give good data. All can give bad data. I'm not fond of a LabRadar but I am very fond of 2 LabRadars, run at the same time. I've documented velocity variance of about 60 fps, due to setup error that I would not have noticed without the 2nd unit. It IS NOT a fault of the machine. Once noticed and re-aligned, the problem was fixed.

I'm still using an Oehler 33 that I bought in 1985. It started to give erroneous readings about 15 yrs ago. Oehler had me send it back and in 1 week I had a new one. I'll probably use it until they stop making D cell batteries[it takes 6].

I had a Pact chronograph for 25 plus years. The only problem was using it on a cloudy day. I gave it to a young guy just starting to reload. I bought a LabRadar almost two years ago and have not been disappointed.

When affordable chronographs hit the market, a few people bought them and were horrified to learn that their favourite factory ammunition or handload didn't launch as fast as advertised. Yikes! Was the chronograph wrong? The reloading manual? The ammunition manufacturer? My technique?

Perhaps you had a favourite recipe, taken from your favourite manual, and when you ran it over the chronograph, there was a big discrepancy! Did you change your load or stop using it altogether? It was probably a load that worked well on game, but you were disappointed that the advertised 2600 fps MV was actually 2400 fps MV!

Some of that might not have been your chronograph's fault. You have to read the instructions that come with the recipe or on the ammunition box. Often, the barrel length and throat condition of your rifle don't match with the test equipment. I used to find this with a lot of used and surplus rifles.

Your 22 inch barrel compared to their 24 or 26 inch test rifle/universal barrel? Or a well used rifle with a cavernous chamber or a different sized bore?

Sometimes, the chronograph isn't the only variable.

Back in the dim times, before affordable chronographs, ignorance truly was bliss!

With all the available chronographs, many very affordable, it would be an interesting article comparing them to something known for accuracy such as the Oehler. I remember you mentioning at one time the ProChrono was also fairly accurate compared to the Oehler and after having the Digital for 20+ years it reinforced my confidence in it and I upgraded to the DLX.

Bingo, John!

Good shootin' -Al

Just how damn accurate do they have to be for the average shooter where the longest shot taken at a critter or piece of paper is 300 yards? 1% or 2% or what. My 35P was a want, not a need as my chrony was more accurate for my needs than my previous method.

I doubt that it matters. -Al

I would argue that, for the “average shooter”, they aren’t necessary at all. For most, as you said, they are a want, not a need.

Maybe it’s “keeping up with the Joneses”.

I would have to agree Steve which is why I am amazed that when a dissing point on one is how inaccurate they are. I know the OP bought a Chrony due to price and it fit his criteria. I can understand JB’s position but also understand that an exact velocity to the Nth degree isn’t going to kill a critter any better, it isn’t going to help me win a 1-2-300 yard group or score match it just makes you feel better and maybe, just maybe it will put me one step ahead of the Joneses.

Might be interesting to go old school throwback method. Useful for extended range testing for energy/velocity?

Ballistic Pendulum

Good one.

On a serious note I read a story where Billy Dixon had somehow chronoed his supposedly borrowed 50.90 Sharps loads before before making his 1500 yard shot. It was said he stated “ I knew exactly how fast that bullet going.”

Sarcasm off.

Amazing how a malcontent can twist things around using part of the truth but far from all the truth

I'm happy with the Chrony.
As was said, I'm good with what I paid, and it's to see if my loads are near where the book says they should be, with all factors involved.
Shot the same loads over it twice now, and same velocities.
Are they accurate ?
Using JBM, and the mil marks in my 10x mil quad super chicken, I smacked a soccer ball sized rock at 580 yards !
Is my old Leica lrf 1200 accurate ?
Another questionable factor involved....

My first "chronograph" was a ballistic pendulum, put together with the directions in P.O. Ackley's first volume of his HANDBOOK FOR SHOOTERS AND RELOADERS. Built it in the basement of the first house I bought, which was outside the "city limits" of the little Montana town I lived in then. That was about the time electronic hand-calculators started replacing slide-rules, and I had one. As far as I could tell, the pendulum worked.

But must also admit that I am not obsessed by muzzle velocity, after going many years without a "real" chronograph, instead actually shooting at various ranges with my rifles to determine the trajectory. But when I started writing about hunting rifles (among the many other subjects I wrote about back then, from Western history to fishing) and realized that an actual electronic chronograph was required to be published--rather than listing "approximate" velocities from loading manuals, which used to be common.

Bought my first electronic chronograph in 1979, when still in college, a unit that hasn't been made in years. It included both "break screens"--made of a grid of thin aluminum glued to equally thin paper--and light-screens. Tested them against each other, and came up with the same numbers. (Oh, and it was one of those chronographs where you turned a dial that pointed toward numbers from 0-9, and wrote down which little red lights beside each number lit up. Then you looked through a booklet that listed the velocity of that series of numbers.) The major test I made was running some Remington .22 Long Rifle ammo through my old Marlin 81 and finding the velocity closely matched the chrono.

That chronograph eventually died in the early 1990s, and since by then more of my income was due to gun writing, I bought one of the early Shooting Chronys, which believe it or not cost $50 from the L.L. Bean catalog. Tried it with the same batch of Remington .22 LR ammo, and the results were very close.

After that went through a bunch of chronographs, including two more Shooting Chronys. Learned the various ways they can go wonky--or work well. Along the way got to visit several professional pressure labs, and learned a LOT--including the fact that EVERY one used an Oehler chronograph of some sort. (As Buford Boone noted, have never heard of anybody testing chronographs for accuracy against anything but an Oehler.)

But again must emphasize that I do NOT believe every handloading hunter needs an accurate chronograph. Though along the way I also learned that muzzle velocity has a far closer correlation to pressure than any of the traditional "pressure signs"--and having accurate velocities can also save plenty of time when testing loads for POI at longer ranges--and am not talking 500+ yards, but even 200-400, depending on the cartridge. All of this eventually saved me a lot of time--and components. (Dunno anybody who doesn't want to save on components these days.)

Might also mention one of the more extreme instances where "published data" did not come anywhere close to reality. A good friend in the gun-writing business bought a 7mm Remington Magnum back when it was still one the hottest-selling rounds. He loaded up some 160-grain bullets and found they shot well with the load listed in the same bullet manufacturer's manual, which supposedly got 3000 fps. He used it for years in western Montana to take big game from deer to black bears and elk, and boy, did it knock the snot out 'em! Man, that magnum sure did a job.

Then he got into gun writing, a few years after I did, and had to buy a chronograph. I can't remember which brand, but it might have been an Oehler, since Shooting Chronys didn't exist then. He found out his devastating "magnum" load got around 2700 fps, about like "modern pressure" loads in a 7x57. But he never shot anything beyond about 250 yards in that steep, timbered country, so even the extremely "slow" bullet still worked great. But he would have been surprised at the trajectory if he shot anything beyond 250 yards.

No, handloaders don't need chronographs--and in fact I have long felt they hamper some handloaders, who're always trying for absolute maximum velocity. But "affordable" models have been around for at least 30 years now, and buying and using one doesn't make any sense unless it's accurate.

It's all about your satisfaction. If, in the future, you wish to get deeper into it, you have that option.

Not too many years ago, we grabbed a box of ammunition off the shelf, or put some handloads together that were reasonably accurate. We trusted the manufacturer or the company that produced the manual. We trusted what was written about our loads. Oddly, everything worked.

Enjoy!

Edited because that Quote, above, didn't format right.
Bryan Litz did just that. It is an excellent chapter in one of his books. I actually think he did the best job of comparing chronographs and explaining how they work that I've ever seen.

And, yes, he used an Oehler as the "Truth" to which all others were compared.

Yep, and it was another major confirmation of my decision to get an Oehler 35P more than a few years ago.

One of the reasons I recommend the ProChrono to handloaders who don't want to spend much on a chronograph was my first afternoon of shooting several rifles for about four hours over both chronographs, with the ProChrono Pal placed a few inches in front of the Oehler. Shot from mid-afternoon until the sun was angling down, and got essentially the same results, with cartridges from the .17 Fireball up, and got basically the same results--though due to the longer distance between the Oehler's screens it's far more meaningful when analyzing stuff like standard deviation. (Am also still amazed by handloaders's who believe the SD from 3-shot strings is meaningful, whether from a small chronograph or an Oehler.)

Have since purchased another ProChrono and it did just as well. But that's sort of aside from the main point, that unless somebody knows their inexpensive chronograph is accurate, there's no reason to use one.

John, I tested my Pro Chrono against a pals 35P and there wasn't more than single digit differences between the two. One of the things that makes a difference on mine is using an cheap furnace filter instead of the provided sky screens.

Good enough for the girls I go with! 😉 -Al

Which, as I posted earlier, is what I did as an armourer. The important thing to add is getting your unit calibrated periodically. What is Oehler's frequency recommendation? ex. a time frequency like once every six months, or hrs of operation before calibration. This would be something those who use a Pro Chrono should follow too. They state that accuracy is +/-.5% of measured velocity or better. For example, a 3000 fps load would be no more than 15 fps out. Say, 2993 to 3008 fps.

This is no different than getting a torque wrench or other precision device calibrated. For example, our torque wrenches were calibrated every six months.

Calibration ensures that what you are using remains accurate. Or, for the Campfire, and to be blunt, demonstrates how anal you are about accuracy.