Home Forums Hunting & Shooting Ask The Gunwriters JULY column--Chronographs

I use my Magnetospeed anecdotally. "Hmmm, I wonder what speed these 190 grain cast bullets really are going out of this Savage M1899 .303?" Statistical averaging and digital/electronic storage and retrieval are totally of no consequence to me. I chose the Magnetospeed purely because of its not requiring the setup of devices out in front of the bench, and its compactness- it rides inside the same soft case that holds my spotting scope. That said, and God help me, I'm seriously considering a Labradar and will do so once I justify spending as much as what I can buy a decent used rifle for. Strange how a rifle loony's mind works...

Buy another 99 instead!

Well, ok then!!

OK, let me start off by stating I’m thought of by most as a down to earth, practical lad. I say that because what I’m about to post will cause many to see me as living life on the edge of sanity. So here we go! I have a custom 257 Roberts (not an AI) built on a pre-64 action. To it is screwed a 23” Krieger barrel. The stock an older Pacific Research fiberglass stock. Optic is a Leupold FX 11 6x36 scope in S&K mounts.
Now the interesting part. With a load of IMR4831 beneath a 115 grain Nosler Partition, in Remington and using Federal 210 primers I’m getting 3180 FPS as measured by an older chronograph AND by a new radar chronograph.
No sticky bolt, no pancake primers at all!
I’m not reporting the powder amount, but it’s north of the Nosler manual and a grain more than Finn Aagaard reported in his excellent book,”Hunting Rifles & Cartridges”.(See page 109)
Contrary to what the above may lead you to believe, my goal is never to wring out the last 10 feet of velocity of velocity in any load; but this time it appears I certainly have.

One thing for sure, getting a chronograph definitely pointed out to me the inaccuracies of judging velocity by the fired primer appearance....



Got an Oehler 35 in the late 90's after using a couple of less than reliable other ones. The plastic housing is getting kind of beat up and I keep thinking that after 20+ years it's time to upgrade, but it keeps on ticking and never lets me down. Plus I wouldn't know what to upgrade to. Nice to read MD is still using his and considers it to still be among the best for a hobbyist type handloader.

Like many here, I mostly use mine these days to keep out of trouble - and it has paid for itself several times over by pointing out potentially big trouble approaching more than once.

Thanks for an interesting and informative article. But my how times have changed. Really, a chronograph from LLBean? I've purchased a few clothing items from them in the past(but no more). Looking thru their catalogs there is nothing that appears even remotely useful for hunting/shooting.

now this brings up another question i need to ask if its cold outside let`s say 0 ,10 below or even 20 below and inside my shooting house its 45 - 60 degrees now i wonder how well a Labradar will work with a 10 inch x 14 inch open window ?

here`s another thought: while using this Labradar chronograph could it cause Cancer ?

Well, I was new enough at the game that I didn't know what to think actually, but I was full up with dogma and that's a fact. It was shortly after that that I read "Rifle Accuracy Facts" by Harold Vaughn and came to the conclusion it's a miracle that anyone can hit anything with a rifle or pistol. We are nothing more than conductors for the Chaos Opera.

As "perfectionists", we tend to expect paying more will obtain perfection. Two of the greatest benefits of the Oehler system, to me, are:

1 - The description of EXPECTED accuracy (they don't claim to be perfect). and
2 - the ability to control the accuracy of your system.

The system lets you set it up whatever way works best for you. Longer spacings are more accurate...and less convenient. I've played around with spacings as long as 18'. I have heard of one shooter that setup a 40' spacing. The 35P lets you go to 15'.

Most of my work is done with 9' or 8' spacings.

I would not put much faith in any chronograph that had a 1' or 2' spacing.

From the Oehler 35P manual:

ACCURACY:
The expected error on any one shot depends on both velocity and screen
spacing. Typical errors are shown in the table. The table assumes good light
conditions, dark bullets, exact screen spacing, and shooting through the
center of the Skyscreen III window. Actual errors under your shooting
conditions will be reliably indicated by the PROOF CHANNEL®.

1 FT 2 FT 4 FT 8 FT
1000 FPS 5 fps 3 fps 1 fps 1 fps
2000 FPS 10 fps 5 fps 3 fps 2 fps
3000 FPS 16 fps 8 fps 4 fps 2 fps
4000 FPS 21 fps 10 fps 5 fps 3 fps

You will typically see the above errors as differences between the primary
and proof channels of a Model 35P as you shoot under "normal" conditions.
PROOF CHANNEL®:


The system alerts you with a flashing display and printed asterisk if there is a
significant difference between the two velocity readings. Differences which
trigger the alert are shown for typical velocities and screen spacings.

1 FT 2 FT 4 FT 8 FT
1000 FPS 42 fps 21 fps 10 fps 5 fps
2000 FPS 83 fps 42 fps 21 fps 10 fps
3000 FPS 125 fps 63 fps 31 fps 16 fps
4000 FPS 166 fps 83 fps 42 fps 21 fps

I expect the above errors from THE BEST sensors. Assuming all other machines use the same quality sensors (probably being overly generous here), they should also have the same expected error.

For my situation, the "hassle" of an 8' spacing is well worth the increase in accuracy.

The Oehler 35P manual is available online. It is well worth the read even if you don't plan to purchase one. Additionally, you can find Bryan Litz's chapter on chronographs online. It is the best explanation I have seen of how chronographs work.

Mr. B Boone - an excellent post. Thank You.




An Update to my earlier post:



This is how I mounted the sky screen IIIs when I upgraded from the IIs.
I haven't had any problems but WANTED them mounted flush.


PIX for Demo only.



photoPUKEIT is NOT cooperating. I'm UNDER the limit of images for free hosting but THEY are being XXXXXXXXXXXX.
I'm contacting them and telling them what I think and the FREE press they are receiving.


Yesterday I decided it was time to fix them like I want.




They are FLUSH with the top of the board.
You'd HAVE to be an INEPT shooter among other things to hit one.

ATST it only takes a couple of minutes if I swapped them back in order to use the Diffusers.

With the screens permanently mounted on a board, set up and take down is quick and easy.



Jerry

ps: they are spaced 5' C - C

Steinert Sensing System AS Super Chrono,made in Norway > has anyone used or purchased one of these chronographs ? i have spent alot of time reviewing new type chronographs this one also works in low light and is much lower priced too it appears but nobody has any in stock right now, it only reads FPS which is all most of us need.

Buford ,

Good post .
How are things going ?

Soup

Soup,

I'm enjoying retirement from the best job in the world. I'm also having a great time consulting, teaching and researching...but on my own schedule.

Exciting things on the horizon for long and extremely long range shooters.

I hope you are doing well.

The first thing that I see is that the bullets need to be supersonic. This would eliminate its use on most handguns and some rim fire rounds. It would also be useless for bow.

Another great MD article.
Another Oehler 33 soldiering on.
10ft spacing 10ft from the muzzle. I have 3 pieces of conduit with screw type connectors. Still kind of a PITA to set up. My last place I had permanent brackets, just place the screens and start shooting.

>yes your right but for the lower price ,ease of setup ,works in low light, rain or snow ,would be perfect for many of us that get sick of setting up our normal chronographs and will work just fine for handloaded rifle ammo.

Great write-up!

I got my 35P about '92 when I was shooting about 6 days a week. I was curious mainly to determine effects of altitude and temperature on established loads. I developed and shot at sea level with range temperatures around 80 or higher, yet all my hunting was in Montana and Wyoming, mostly late season when the temperatures were at freezing and many times near zero. Learned a lot, but mainly that at most reasonable ranges, under 300 yards, 300fps through a 338 Win Mag, didn't make much difference for a clean kill. But that started my quest for temperature tolerant propellants, which led me away from my beloved RL22. I hauled my chronograph to my hunting areas and fired over it in those low temperatures several times to settle on other propellants. Never had a moments problem with my 35P.

I have the 35P and the LabRadar. While I’ve enjoyed my Oehler for years, the LabRadar’s ease of setup has sent my Oehler to the attic. Dealing with the Oehler at a crowded range (even a private one) is a huge buzzkill. If I had my own place to shoot, it might be different.

As for chronos in general, I find that being able to see velocity level off as I increase charge weight is invaluable.

Great article. John! Tahnk You!

I moved away from Chrony, first, and Prochrono, second, as soon as MagnetoSpeed became available. It worked quite well, though the weight at the tip of the barrel changed the harmonics and altered both the grouping and the point of impact of the gun.

Not a big deal, as it just meant shooting a bit more, checking speeds first and concentrating on accuracy thereafter.

Then, LabRadar appeared on the scene, I sold my MagnetoSpeed to a good friend and bought one for the sake of its easier set up and beacause I could check speeds while paying attention to groups and point of impact.

Regarding LabRadar... From one day to another I have recorded different speeds with what I believe to be exactly the same load and gun. It has happenede to me twice, with two different guns... It might be my error, due to some mistake in my writing down data into reloading notes but I do not think so. I need to recheck, of course but I am 99,9% percent that my notes are correct. So the question is, will de LabRadar produce different readings due to (slightly) different positions and/or angle relative to the muzzle and barrel axis? If I place it way off course I will not get a reading, but if I do get a reading will it be the same, alwasy, regardless a slight difference in the positioning of the LabRadar?

Thank You!

Alvaro

Alvaro,

I have seen different results from day to day when chronographing the same load with several different chronographs. This can be due to several factors, but usually not the chronograph as much as temperature. Many powders are affected to some degree by warmer or cooler conditions.

But variations can also be due to the usual practice of most handloaders, who chronograph 3 or (at most) 5 shots of a certain load. As I've mentioned in other places, the ammo factories I've visited usually chronograph several dozen rounds of the same load before coming to any conclusions about velocity and consistency--and they're working indoors, in far more controlled conditions than most handloaders.

What sort of variations are you seeing from day to day?