Who's chrony data do you trust?

[jmorris]

Many of us, myself included, were loading very good accurate ammunition long before a chronograph crossed the door threshold.

Unfortunately it takes more than a chronograph to load very good and accurate ammunition. Kind of like it takes more than a timing light to tune an engine, it's just another tool in the box, so to speak.

 

[forrest r]

They come from my own tests holding an 11 pound 308 Win shooting max loads of 168's with the rifle held half an inch off my shoulder then pulled as hard as possible getting over 50 fps difference in average muzzle velocity. Someone on another forum posted 40 fps difference between shouldered and lose held rifles on a bench top. A friend weighing 260 lbs who dwarfed pro football tackles shot his 308 Win rifle's bullets over 90 fps faster than his 130-pound son did; he held it tight, his son, loose.

My 100 fps quote was the maximum difference in average or mean muzzle velocity numbers, not the standard deviation numbers you mentioned.

Your average (mean) fps number spread is 8 fps. I don't know what the weight of your Lead Sled is, but if it plus added weights are 35 pounds and the rifle weighs 11 pounds, for the bullet and velocity stated, the sledded rifle has 1.69 fps recoil velocity and the rifle alone has 7.06 fps free recoil velocity. Was your Sled firmly bolted to the bench so it didn't move at all and held the rifle perfectly still? If not, it has a tiny amount of movement backwards while the bullet's in the barrel.

Shoot that rifle resting atop something on a bench holding it as hard as you can against your shoulder. Or do the same thing slung up in prone. Then check the bullets muzzle velocity to compare what it did in free recoil resting on bags.

Nice write up
That's the biggest issue with chronographs, people don't shoot straight over them.

 

[forrest r]

I've owned different chronographs for going on 25+ years now. Shot.a lot of ammo over them over the decades. Years ago a bunch of us got together and did a bunch of testing with chronographs. 20+ shooters and 10+ different chronographs, had e-cheapo's up to the top of the line oehler 35 there. When the smoke cleared they all read within 10fps of each other.

Do I believe what someone else prints from their chronograph tests??? Why not!!! Gives me something to look at and compare to what other people have tested and posted. 1 data point doesn't mean much to me but I'm glad people post their results. I typically go to 6 or 7 different sights and do searches when I'm looking at a bullet or powers for a caliber. Or the charestic's of a powder or bullet in different calibers, bbl's, etc.

Most people only use a chronograph to tell them the velocity of their loads. Any tool is only as good as the person using it. Things like reloading errors, load densities and mechanical issues can easily be picked up on with a chronograph that would take years and 1000's of rounds to find by the old tried and true put on paper method.

 

[GBExpat]

Who's chrony data do you trust?

My Chrony Beta Master w/maxed out NVRAM.

 

[Wreck-n-Crew]

Until I was exposed to the Magnetospeed, I never looked into getting a chrony

So I got an MS V3 a little while back. What an amazing tool.

But this also opened up a problem...based on some videos I've found, alot of the standard chronies are very inaccurate. Here's a quick vid.

If there is one thing that most people (who have been around long enough) think when reading a statement like that^^^

Which also leads me to the idea, most of the FPS info people are posting is using data from an unreliable electronic device. And even if you do believe some chrony setups are high quality with good data.. nobody lists the model of chrony they are using.

I don't trust your $70 Cabela's chrony.

<<<<or this, is that someone "justified an expensive purchase" with reasons (or excuse) others are subpar.

I think I (as well as others) would be more open to the idea of a better Chronograph if it wasn't "insulting" other chronographs. Especially when I have found most claims such as "How great this pistol is" and "how crappy that one is" too be totally biased, unfounded, and often plain wrong from personal experience. I'm sure I'm not alone.

 

[Bart B.]

Ron, about this:

Anyway, with the setup I had, as pictured, I could not get close to 100 FPS in my standard deviations.

Again, you're using your standard deviation numbers. I never did. I used average velocity. How much bigger is your average/mean numbers than the standard deviation ones? Quite a bit, in my opinion.

Again, I use 100 fps as a reference in average velocity spreads as it's the one that encompasses all those I've done my self as well as others who've passed on their numbers from their tests to me. I could also use 96, or 98 but didn't think it mattered. A box holding your toys has to be a little bigger than all of them clustered close together, doesn't it?

 

[buck460XVR]

I think I (as well as others) would be more open to the idea of a better Chronograph if it wasn't "insulting" other chronographs. Especially when I have found most claims such as "How great this pistol is" and "how crappy that one is" too be totally biased, unfounded, and often plain wrong from personal experience. I'm sure I'm not alone.

You are not. That and if one looks hard and long enough on the internet there is probably a video out there to justify/defend any choice. What was really of interest to me was the minuscule amount of extreme spread shown by the Magnetospeed. That was either some really well loaded ammo or something else was up.

 

[Bart B.]

So how did thousands of bench rest and 1000 yard Palma match shooters {I'll add match rifle shooters for 200 through 600 yard matches} developed their match winning accuracy without the aid of a super precision chrono for decades?

Some of them used the same loads the winners did. I did that and never developed any load for existing bullets for given cartridges. Mine all tested as accurate in my barrels as the winners did in their barrels. Never changed a given load across all the barrels chambered for it.

 

[Reloadron]

Ron, about this:Again, you're using your standard deviation numbers. I never did. I used average velocity. How much bigger is your average/mean numbers than the standard deviation ones? Quite a bit, in my opinion.

Again, I use 100 fps as a reference in average velocity spreads as it's the one that encompasses all those I've done my self as well as others who've passed on their numbers from their tests to me. I could also use 96, or 98 but didn't think it mattered. A box holding your toys has to be a little bigger than all of them clustered close together, doesn't it?

Bart, the spreadsheet numbers I posted include Standard Deviation and Average Velocity as well as each individual shot. Interesting as Free Recoil comes in at 2834 FPS and the Lead Sled comes in at 2842. Anyway it's all in the spread sheet I posted. Anyway, the delta for average velocity was only about 8 FPS. That was 50 rounds and I am just not seeing a big difference. I will run it again when we see some warmer weather and try a few other methods and see what I get.

Ron

 

[JPDeacon]

Been loading for handguns and rifle for more than half-century with good results without a chrony. Got one for Christmas a couple years back..good little tool. I use it mostly to check my reloads, in different weapons, against the many (way too many) reloading manuals I've collected. I don't shoot competition or hunt anymore but do love to spend time shooting different targets and making noise, so I don't get hung up on the Chrony results.

 

[hdwhit]

And in rare cases mine has given readings that are pure nonsense. It doesn't happen often, but when it does you''ll know it.

Agreed.

When my chronograph (so old it doesn't have a name or number printed on it) gives me a velocity of 3,256 fps from my Taurus PT111, 9mm Parabellum pistol, I know to discard the result.

 

[Swampman]

Ron, about this:Again, you're using your standard deviation numbers. I never did. I used average velocity. How much bigger is your average/mean numbers than the standard deviation ones? Quite a bit, in my opinion.

Again, I use 100 fps as a reference in average velocity spreads as it's the one that encompasses all those I've done my self as well as others who've passed on their numbers from their tests to me. I could also use 96, or 98 but didn't think it mattered. A box holding your toys has to be a little bigger than all of them clustered close together, doesn't it?

If there's no difference between 96 and 100 feet per second, why do we bother measuring at all?

I always thought that ballistics was a science.

If truth, facts and actual measurments don't matter, why should anyone even bother with a chronograph?

 

[jmorris]

Some of them used the same loads the winners did. I did that and never developed any load for existing bullets for given cartridges. Mine all tested as accurate in my barrels as the winners did in their barrels.

That is a good reason to not take data your chronograph(s) give you as the "be all and end all". Numbers are fun to talk about and do math with but results are more important than calculations, to the winners at least.

 

[Walkalong]

If there's no difference between 96 and 100 feet per second,

There is no appreciable difference in those two figures in the real world. We have bigger ES numbers than that most of the time.

That is a good reason to not take data your chronograph(s) give you as the "be all and end all". Numbers are fun to talk about and do math with but results are more important than calculations, to the winners at least.

Exactly.