Fps variation

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mckay5858

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Hey,

Was at the range today using my chrony for the first time. My hand loads had a total variation of 56 fps, 2853 being the lowest and 2909 being the highest. This is on a 223 pushing a 68 gr hornady a max with varget. I'm wondering is that good/bad/average for a spread? I don't really have anything to go against. I was pretty careful measuring the powder charges but didn't sort any cases or bullets. Any feedback is appreciated. Thanks!
 
At long range, that variation could cause some vertical stringing. The further you go, the more effect it'll have on your group. At 300yds or less you wont be able to tell at all. At maybe 500yds you'll start to see some differences. If you go to 1000yds with a 56fps ES you will definitely see it.

If you aren't shooting past 200-300yds, I would ignore it.
 
What kind of chronograph? The chrono you are using may allow that much variation. The better the chrono the more accurate it is.

On some chronographs there is no way to get to single digit variations because they are not capable of it.
 
An extreme spread of 56 fps over several (I assume) rounds is perfectly normal in my experience. I've seen larger. I pay more attention to the standard deviation a load produces than to extreme spread.
 
mckay5858 said:
It's a chrony

I think I'm alright with it. Might try some lapua brass and see if I can get it tighter.
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Why? What benefit do you expect from a smaller deviation? Simply making a smaller number for the sake of making a smaller number is entirely pointless. There are dozens of factors that alter where a bullet will impact. Muzzle velocity is only one of them. There are potentially many factors that govern bullet velocity, powder charge being only one of them.

A small velocity spread is literally no guarantee of accuracy. There is nothing wrong with the velocity spread you have currently. Go shoot your rifle and forget about it.
 
One should strive to get the ES down below 20 fps however it is not always possible...........I had a 22-250 that with one quite light load shot one hole groups measuring less than 3/8 inch for 5 shots........the ES was 120 fps on that load, so............I still strive for less than 20 fps ES. I find case capacities and inconsistent bullet depth to be the 2 largest contributing factors to big ES..........
 
c-fbmi said:
One should strive to get the ES down below 20 fps however it is not always possible...........I had a 22-250 that with one quite light load shot one hole groups measuring less than 3/8 inch for 5 shots........the ES was 120 fps on that load, so............I still strive for less than 20 fps ES. I find case capacities and inconsistent bullet depth to be the 2 largest contributing factors to big ES..........
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Why? The ONLY thing of any importance is the accuracy of the load. Velocity spread means nothing in comparison. It is just a number. If the load is accurate within the range you intend to shoot, leave it alone. NOTHING ELSE MATTERS.

Velocity spread will only ever make any difference at very long ranges. I'd say maybe in excess of 500 yds. The vast majority of shooters will never exceed that kind of distance.

Additionally, the ES values being thrown around are essentially meaningless without an understanding of statistical analysis, mean and standard deviation. If you have 10 velocities all clustered together and one or two outliers then quoting ES is wrong. Another sample group of ten velocities with an even distribution of velocities across the spread is an entirely different thing.

Without an understanding of the difference this discussion is all verbal masterbation. It may be fun but it doesn't really accomplish anything.
 
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Suputin said:
Why? The ONLY thing of any importance is the accuracy of the load. Velocity spread means nothing in comparison. It is just a number. If the load is accurate within the range you intend to shoot, leave it alone. NOTHING ELSE MATTERS.

Velocity spread will only ever make any difference at very long ranges. I'd say maybe in excess of 500 yds. The vast majority of shooters will never exceed that kind of distance.

Additionally, the ES values being thrown around are essentially meaningless without an understanding of statistical analysis, mean and standard deviation. If you have 10 velocities all clustered together and one or two outliers then quoting ES is wrong. Another sample group of ten velocities with an even distribution of velocities across the spread is an entirely different thing.

Without an understanding of the difference this discussion is all verbal masterbation. It may be fun but it doesn't really accomplish anything.
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And that would be your opinion.............

Extreme spread as well as SD and mean avgs are all indicators of consistency.......I try to get my loads to a meaningful level of consistency using all the data available to me. To say that considering ES or SD is nothing more than verbal masturbation, kinda flies in the face of load consistency, and generally speaking consistent loads will tend to be accurate loads, if you have found your rifles node(s). One should never discount ANY information available to them when working up loads, however one should also not consider any one data source as being the "end all, be all" of loading consistency either. The trick to making consistent loads, is the ability to place the correct amount of importance on the data you collect..........none of it is worthless, as you seem to believe, and none of it is priceless either..........it is all valuable information and together it paints a picture, the more data sources at your disposal the more detailed the picture. One cannot ignore a 100 fps ES even though it shoots sub MOA @ 100 mtrs. Given this information I would obviously continue to work with this bullet in and around the avg velocity range but would then play with seating depths, change powders and try hotter or cooler primer. I have also found that high ES are usually a product of light loading, and that as the pressure goes up while looking for my best velocity/accuracy node, ES goes down. Very few of my hunting loads have an ES over 20 fps and this is not because I am chasing a low ES it's just seems to be the way it works, higher pressure = lower ES.
 
c-fbmi said:
One should strive to get the ES down below 20 fps however it is not always possible...........I had a 22-250 that with one quite light load shot one hole groups measuring less than 3/8 inch for 5 shots........the ES was 120 fps on that load, so............I still strive for less than 20 fps ES. I find case capacities and inconsistent bullet depth to be the 2 largest contributing factors to big ES..........
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Thanks that is what I was looking for. Will try looking at and batching my brass first.

Supporting, of course I'll keep shooting but I'm still going to try and get it closer. Why? Same reason anyone works at anything, to get better.
 
mckay5858 said:
Thanks that is what I was looking for. Will try looking at and batching my brass first.

Supporting, of course I'll keep shooting but I'm still going to try and get it closer. Why? Same reason anyone works at anything, to get better.
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Better at what? If you get a single digit ES and the group size goes to sh!t, will that qualify as "better?" You are entirely missing the point. ACCURACY is the only parameter by which a shooter should be measuring improvement.

Without being able to properly evaluate velocity spread statistically you have no manner to measure improvement. Gross ES is completely and utterly pointless and stupid.
 
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