Reloading voodoo

rimfiremac

rimfiremac

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Well I chrony'd a few different loads last evening, including one for the 208 Amax with Re15 and also a gold standard 155 Scenar+45.5 gr Varget for comparison. The results gave a good demonstration of the voodoo associated with reloading. The 208's had an ES and SD of one, yes 1, over five shots, and shot into 2.25" at 200 yards. The 155's had an ES of about 35 and SD of 15 and shot into an inch.

Guess I found the wrong node for the 208's, but it was very peculiar to see such a uniform load shoot so poorly.
 
now you know why I leave the chronie at home.

target shooting is about holes in paper, not data in a spreadsheet.

I bet you can also find an accurate load for the 208gr amax.

Once you work through the Voodoo, you will find that there is alot of science in load tuning.

It really isn't magic.

Jerry
 
Uniform velocity is not what produces an accurate load, but rather a consistent and precise load.

Bullets that leave the muzzle all at the same velocity are good for LR conformity (due to low ES and SD), but finding a MV where all the bullets leave the muzzle at an anti-node of the barrel harmonic wave is what produces optimal accuracy. Even if all the bullets leave the muzzle at the exact same velocity, but do so at a node of the harmonic wave, then the accuracy of the load will suffer.
 
One of the problems with chronographs is that they spit numbers out, but often then mean almost nothing. The SD and ES on only a few shots is essentially meaningless from a statistical point of view.

I ladder test at 300 meters and ignore the SD and ES. I do track velocity but only if I have at least 9 shots to average, and even then I throw out ones that do not smell right. My view is that powder weight in many cases is a better indicator of actual velocity than measured velocity. But it is good to know once you find a sweet spot what the velocity is so you can transfer it to other bullets and weights.

It seems to me that SD and ES are helpful in the fine tuning of a load once you find the sweet spot velocity, especially if shooting long range. Short range, perhaps not even necessary.
 
I basically use my chrony now to verify that I don't have wildly too much or too little velocity, indicating pressure issues. I also use the average velocity to calculate a rough ballistic curve that I can use as starting point for adjustments for distance. Hard to fine tune a zero if your bullets miss the target to start and you don't know where to correct from.

After that, I am happy to put the damn thing away. They are such a pain to set up and take down that frankly when I can shoot without it, it is a relief.
 
Bolivar said:
I basically use my chrony now to verify that I don't have wildly too much or too little velocity, indicating pressure issues. I also use the average velocity to calculate a rough ballistic curve that I can use as starting point for adjustments for distance. Hard to fine tune a zero if your bullets miss the target to start and you don't know where to correct from.

After that, I am happy to put the damn thing away. They are such a pain to set up and take down that frankly when I can shoot without it, it is a relief.
Click to expand...

BINGO....

If I am expecting 2800fps and I get 2600fps, ADD powder.

If I am at 2950fps, maybe good maybe not but I know that pressures are on the toasty side of norm.

But to focus on whether is it 2823fps or 2844fps, couldn't care less as that is within the error of the clock.

Jerry
 
Try going a few grains below the book recommended max and load 5 of each in .2gr increments and shoot some groups. I went up in .1gr increments with my 17FB. It has a pretty small case though.
 
The barrel used is a 10-spin stock Savage barrel on a 10FP. It stabilizes no problem at all with the 208.

While I was at it, I ran some 22LR thru the crony while shooting groups at 100 yards. Even at 100 yards, the effects of a hot round or a slow round were very apparent. A round averaging 1050 fps will be significantly affected by velocity variations- in this case the ES was nearly 100 fps with an SD of 21 or so, and a flier high or low directly correlated to the velocity. Those occasional rounds that come out 40 fps hotter will go an inch and a bit high, and the slow-pokes similarly low. Ammo was RWS Rifle Match.

I appreciate the merit of sticking to loads that shoot well over those that shoot uniformly- I was no less surprised about the peculiarity of my results though. A repeat test today showed a 178 load that had an ES of 80 or so, but shot into a half minute vertically at 200. Putting the speedometer on these rounds was helpful in that they run 100 fps slower out of the Savage than out of my prior 308, and are a little on the slow side.

Cheers to all for the comments- helpful in piecing it all together.
 
I've seen no statistical correlation between SD or ES and group size. The concept sells chronographs, and I expect tons of components, striving for the "consistent" load, but each arm is a law unto itself, and they know not the laws of statistics.
 
ykkid said:
I've seen no statistical correlation between SD or ES and group size. The concept sells chronographs, and I expect tons of components, striving for the "consistent" load, but each arm is a law unto itself, and they know not the laws of statistics.
Click to expand...

If you are judging correlation of SD/ES by size of 100yd groups then you likely are correct. You are wrong about no correlation at say 1000yds and the "laws of statistics" do apply.

NormB
 
You can have an ES of 100 fps and still group sub MOA at 100 yards, but an ES of only 25 fps can result in a couple of inches being added to your groups size at 1000. If I shoot a really tight group at 100, but find that the ES is inconsistent, there is little point in attempting to shoot that load at long range. I think the key is to find a balance between accuracy, velocity, and consistency before investing the time and expense in long range testing. To that end a chronograph is a valuable tool if the information it generates is interpreted correctly.
 
Apologies to the OP, but I can't control the impulse to hijack.

When it comes right down to it, is it not a mistake to treat Chrono's as if they were some precision instrument that spits out highly accurate empirical data? The external and uncontrollable influences alone would suggest otherwise and I've measured carefully made batches of ammo on my unit and obtained a credible looking average velocity, then found an equally credible looking average velocity measured on a different unit to be,,, different.

I've concluded that my (or any) chrono is relevant but relative. There's a claimed standard to which these things are built, but seriously, don't you get what you pay for ? These things sell for a lot less than lab equipment prices.
 
HKMark23 said:
When it comes right down to it, is it not a mistake to treat Chrono's as if they were some precision instrument that spits out highly accurate empirical data?
Click to expand...
Bingo!
That's why the voodoo aspect creeps in here. I found many moons ago that cloudy/sunny days affects the way my Chrony would behave. Accurate? Hardly! Which day did I get the best results?

The main components for consistency with SD/ES is primers, powders, neck tension and seating depth which concerns us the most for 1,000yds shooting. I can only spend so much time wearing out barrels then find I have a different lot of primers/powders or some components aren't available at this time. I've seen and tested so called match primers that didn't perform better than their standard ones from lot to lot.
 
From the chrony-accuracy angle, say that the error in the machine is 2%- that yields 50 fps based on a 2500 fps average, exceeding the SD in most cases. An error of 0.5% is still 20 fps, which is the SD ballpark I've been getting on lots of loads. I'll be a while scratching my head on this one.

Maybe its all for entertainment?
 
I can only hope the extra money I spent on an Oehler was worth it. I don't mind the idea of my display velocity being high or low by half a percent, provided that each round I fire across the screens has the same amount of error, in other words that the velocities I measure for a shot string have relevance to each other. I was under the impression that even the measurements made with inexpensive chronographs compared favorably with the results from Doppler radar. The greater distance between the screens of the Oehler to my way of thinking should produce more accurate data, similar to a balance beam scale being more precise with a longer beam, all else being equal.

Certainly where and when testing takes place has an effect on velocity. I noted that my loads for the .375 Ruger were significantly lower than Gate's, but I expect that living in BC his range is at least a couple thousand feet above sea level, and his data was collected in warm weather whereas my load testing was done at sea level and at -32 degrees, and in the cold the Oehler seems to work better than a Chrony.
 
Oehler is certainly the gold standard and you should be able to get the rated error on the clock from them.

Maybe it is tighter then other makes????

the CED chronies have a strong following and they seem to be considered stable????

There really is no way to know if a device is always reading high or low unless you have a velocity standard. I know of nothing that will generate a speed value that can be used to calibrate a chronie.

You can shoot 22 match ammo but that is open to as many variables as any other ammo.

I am not saying a Chronie is wrong. I am just saying the data it generates may not be right.

Jerry
 
Did I hear wrong or is the venerable Oehler 35 no longer available ?

I have the older (silver) CED which can be used with screen separations out to 8 ft and has IR lighting but the Oehler was always considered top dog. I'd have bought one but understood that, except for the lab rat model $$$$, they were off the market.
 
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