Help with chrono result in graph form

[Benjo]

Hi bit of background,I’ve been shooting and reloading a while and based in Sheffield uk.
In late December I chopped my finger off and after surgery which was a great success,I was stuck home for 3 months.during this time I started watching YouTube reloading vids.
Eric cortina
F class John, and many others.being bored I started buying better equipment to cheer myself up lol
Area 419 press,amp annealer,Redding dies,21st century gauge,magneto speed v3 the list goes on hahaha
£6000 later and I’ve got a top end setup.

So here’s where I need help with my .223 load for my RPR 1/7 twist
Lapua brass.VV N140,Berger 77gr,cci primer
First graph is 3 shot string .3 gr increments
Graphs 2&3 are the nodes I found below and above working in 3 strings .1gr increments
I’m new to chrono and graph analysis so what’s your thoughts from experience which looks like the best powder node?
Thanks in advance

 

[phlegethon]

They are all the same. Noisy samples of linear increase in velocity. There are no nodes. Just pick a speed.

 

[Benjo]

They are all the same. Noisy samples of linear increase in velocity. There are no nodes. Just pick a speed.

So the 23.6&23.7 both have same es/sd and average velocity is not a node ?

 

[rustyinbend]

I'd like to know if there are any pressure signs like heavy bolt, cratered primers, ejector marks, etc. That's how you get a sense of the upper end of the velocity curve. Then you back off and look for a flat spot.

 

[Bacarrat]

I think you still have more to go on the powder charge. Seems very slow with those components. You should be close to 2800FPS

 

[Benjo]

I'd like to know if there are any pressure signs like heavy bolt, cratered primers, ejector marks, etc. That's how you get a sense of the upper end of the velocity curve. Then you back off and look for a flat spot.

Got some primer crating at 24gr but everything else was fine no issues.it’s the 2nd two graphs I’m struggling with? 23.1 has lowest es/sd but .1 above and below aren’t good.
23.6&23.7 are good and almost identical and velocity is similar at 23.8? Would this make 23.7 a good powder charge?

 

[rustyinbend]

Got some primer crating at 24gr but everything else was fine no issues.it’s the 2nd two graphs I’m struggling with? 23.1 has lowest es/sd but .1 above and below aren’t good.
23.6&23.7 are good and almost identical and velocity is similar at 23.8? Would this make 23.7 a good powder charge?

Load up 10 and shoot for groups. Then test at distance. If you've hit light pressure, backed off, and found a flat velocity spot ... then it's time to test for group sizes first, and then accuracy at distance (500 yards or further).

 

[b6graham]

So the 23.6&23.7 both have same es/sd and average velocity is not a node ?

no. it's a small and irrelevant sample size

 

[Evintos]

What do your targets look like?

 

[Benjo]

Load up 10 and shoot for groups. Then test at distance. If you've hit light pressure, backed off, and found a flat velocity spot ... then it's time to test for group sizes first, and then accuracy at distance (500 yards or further).

I did a seating depth test on both 23.1&23.7
and got a great result with 23.7.
I’ve only got easy access to 100yrd range but got a day booked at a long distance range in a months time it’s 4 hours a way so wanted a good load to take with me

 

[b6graham]

load up 23.7 and have fun

from the limited data it looks like a good point even if a little slow

 

[Benjo]

What do your targets look like?

Looked very consistent at those charge weights,played with seating depth and got this with 23.7

 

[Benjo]

no. it's a small and irrelevant sample size

Thanks very helpful

 

[rustyinbend]

no. it's a small and irrelevant sample size

Sometimes a couple of data points is all the "Ladder Gods" are willing to give. It's enough to test for groups, and then distance if groups look good at 100-yards. IMHO

 

[Evintos]

Got some primer crating at 24gr but everything else was fine no issues.it’s the 2nd two graphs I’m struggling with? 23.1 has lowest es/sd but .1 above and below aren’t good.
23.6&23.7 are good and almost identical and velocity is similar at 23.8? Would this make 23.7 a good powder charge?

IMO, this where you look at the target and see how much point of impact shift there is if any on either side of 23.7gr (or at any of the other powder charge weights) and see how much of a window you have in acceptable velocity ES. It does no good to have low sd/es that can't be maintained in varying environmental conditions (example, 20*F temperature change) especially if your powder is slightly more sensitive to temperature variations. Something to consider.

 

[Benjo]

Big thank you to everyone who’s added constructive advice,much obliged.it’s difficult to get advice in the uk either they can’t help or won’t help

 

[Baron23]

Thanks very helpful

He actually was being helpful if being a bit terse about it.

Forget the videos, forum posts, or really anything else and ask yourself how you can increase a propellant quantity and not have a velocity increase. You cannot.

What you have is that at each propellant weight there will be velocity variation from everything like slight difference in case capacity to slight errors in charge weight to slight differences in neck tension and probably a bunch of factors I don't even know (because yes, I'm def no expert). A data set of only three shots at a given powder charge are not enough data points to get rid of the noise and see what you really have for statistically significant performance.

Take 30 or more shots at a given powder charge and chrono them. I would bet you large that you can pick out three shots from that larger set that will give you just about anything you want (flat spot, very small ES, very small SD).

Whatever charge weight you pick, keep collecting chrono data on additional shots and keep adding it to the set and determining ES/SD. You will see MV/ES/SD converge on stable values that are very most likely not what you got from looking at the data of three shots. You will see what @b6graham was talking about.

And yes, there will be many people who will tell you that they've been doing OCW or something similar since before the last ice age and it works. Well, good for them and if it gives them confidence in their loads, all the better. But any statistician will tell you that its bunk and you can prove it to yourself with a chrono.

 

[b6graham]

He actually was being helpful if being a bit terse about it.

Forget the videos, forum posts, or really anything else and ask yourself how you can increase a propellant quantity and not have a velocity increase. You cannot.

What you have is that at each propellant weight there will be velocity variation from everything like slight difference in case capacity to slight errors in charge weight to slight differences in neck tension and probably a bunch of factors I don't even know (because yes, I'm def no expert). A data set of only three shots at a given powder charge are not enough data points to get rid of the noise and see what you really have for statistically significant performance.

Take 30 or more shots at a given powder charge and chrono them. I would bet you large that you can pick out three shots from that larger set that will give you just about anything you want (flat spot, very small ES, very small SD).

Whatever charge weight you pick, keep collecting chrono data on additional shots and keep adding it to the set and determining ES/SD. You will see MV/ES/SD converge on stable values that are very most likely not what you got from looking at the data of three shots. You will see what @b6graham was talking about.

And yes, there will be many people who will tell you that they've been doing OCW or something similar since before the last ice age and it works. Well, good for them and if it gives them confidence in their loads, all the better. But any statistician will tell you that its bunk and you can prove it to yourself with a chrono.

Looking at his graph 23.5-23.8 have an overlapping charge. Thats a VERY large 'node' especially for a 223

Also looking at an SD of 8. That's an ES of roughly 50 in terms of real life data. Which the 23.5 and 23.8 charge start to show with their much larger spreads. This could be anything from individual case volume/weight to neck tension to actual charge weight (assuming higher than .02 accuracy capable from an fx120 which is give or take a kernel weight)

First three shots through a new 6.5CM barrel with berger factory 140 ammo had identical velocities and shot a tiny group. 20 shots later its more like a ES of 20ish and SD around 6. With a 1/2"-5/8" total group.

Cherry pick any 3 data points from that barrel and you'll shoot in the .01" with an ES in small single digits. Look at all the chrono data over 10+ range sessions and you start to see the real picture

You can do the same thing with group size. The rifle could shoot a 1/4" group EVERY single time you shoot a group. But the average POI moves around the POA each time and its really a 5/8" gun

 

[Feniks Technologies]

So the 23.6&23.7 both have same es/sd and average velocity is not a node ?

Here’s what your 3 shot 8.5sd data really means:

You can be 95% confident your actual SD is in this range:

4fps - 53fps

Which means your ES 95% of the time on either end of that spectrum will be 20 or up to 200.

Obviously you won’t be up around a 50sd. But this illustrates how uncertain your data is for predicting what the rifle will do in the long run.



TLDR: your data is far, far too little to mean anything at all except the general velocity each charge weight will exhibit. And even then some won’t be right as flat spots are just variance in velocity when one charge weight exhibits the high side of its ES and the next charge weight up exhibits the low side of its ES. They overlap and appear to be flat spots. Which is just not how it works.

 

[Benjo]

He actually was being helpful if being a bit terse about it.

Forget the videos, forum posts, or really anything else and ask yourself how you can increase a propellant quantity and not have a velocity increase. You cannot.

What you have is that at each propellant weight there will be velocity variation from everything like slight difference in case capacity to slight errors in charge weight to slight differences in neck tension and probably a bunch of factors I don't even know (because yes, I'm def no expert). A data set of only three shots at a given powder charge are not enough data points to get rid of the noise and see what you really have for statistically significant performance.

Take 30 or more shots at a given powder charge and chrono them. I would bet you large that you can pick out three shots from that larger set that will give you just about anything you want (flat spot, very small ES, very small SD).

Whatever charge weight you pick, keep collecting chrono data on additional shots and keep adding it to the set and determining ES/SD. You will see MV/ES/SD converge on stable values that are very most likely not what you got from looking at the data of three shots. You will see what @b6graham was talking about.

And yes, there will be many people who will tell you that they've been doing OCW or something similar since before the last ice age and it works. Well, good for them and if it gives them confidence in their loads, all the better. But any statistician will tell you that its bunk and you can prove it to yourself with a chrono.

Very interesting reply and I’ll certainly take on board what your saying,but I will rebuttal with something I did notice,before using the chrono I shot 5 shot groups x2 of these powder charges and found consistent .8 moa groups with it opening up and not being consistent at 23.4.This left me at a loss as to where to go next.then I bought the v3,chronographed the same loads and it confirmed es/sd perfectly with my original group results.the proof is in the pudding as the saying goes.I really was just looking for advice as to which charge weight looked optimal between the 2 as I’m new to looking at the data in this format. Thanks for the reply and it’s definitely food for thought

 

[Benjo]

Looking at his graph 23.5-23.8 have an overlapping charge. Thats a VERY large 'node' especially for a 223

Also looking at an SD of 8. That's an ES of roughly 50 in terms of real life data. Which the 23.5 and 23.8 charge start to show with their much larger spreads. This could be anything from individual case volume/weight to neck tension to actual charge weight (assuming higher than .02 accuracy capable from an fx120 which is give or take a kernel weight)

First three shots through a new 6.5CM barrel with berger factory 140 ammo had identical velocities and shot a tiny group. 20 shots later its more like a ES of 20ish and SD around 6. With a 1/2"-5/8" total group.

Cherry pick any 3 data points from that barrel and you'll shoot in the .01" with an ES in small single digits. Look at all the chrono data over 10+ range sessions and you start to see the real picture

You can do the same thing with group size. The rifle could shoot a 1/4" group EVERY single time you shoot a group. But the average POI moves around the POA each time and its really a 5/8" gun

Does this mean I shouldn’t bother with these results? Or that it looks promising? I’ve jumped down this rabbit hole and now I’m lost in the warren lmao

 

[rustyinbend]

Does this mean I shouldn’t bother with these results? Or that it looks promising? I’ve jumped down this rabbit hole and now I’m lost in the warren lmao

Ladder to light pressure
Back off a bit
Do a no-pressure-signs ladder
Find a flat spot
Shoot for groups
If you like the groups ... shoot at distance
Be happy ... you've succeeded in Load Development 101 !!!

Too much machination on this forum can drive you crazy. I know ... I am.

 

[Benjo]

Ladder to light pressure
Back off a bit
Do a no-pressure-signs ladder
Find a flat spot
Shoot for groups
If you like the groups ... shoot at distance
Be happy ... you've succeeded in Load Development 101 !!!

Too much machination on this forum can drive you crazy. I know ... I am.

Much appreciated

 

[RegionRat]

Big thank you to everyone who’s added constructive advice,much obliged.it’s difficult to get advice in the uk either they can’t help or won’t help

Sorry to hear that you have had some bad luck there, but keep trying.
I know I am out of the loop these days, but my old shooting colleagues there in the UK didn't used to be that way at all.

In fact, they were typically very open and helpful to local rookies in the times I spent with them in your country.
The professional soldiers and scientists I worked with there were top notch people in many ways.

Near Sheffield, you should be able to find out where they are shooting these days as I am told they (and the public) had to leave the military range cause even the army had to stop live fire at that venue. I doubt they all quit shooting, or that they had to go very far to find another venue.

I will venture a guess that anywhere we go, we could find some bad luck with people who are too wound up to stop and help a rookie, but I am also guessing you just need to keep looking. Give the local shooting matches a visit or two and you will find the right folks to help you out.

 

[Benjo]

what part of England where you based?
Apparently there was a incident involving reloaded ammo on a MOD range and the MOD will only allow factory ammo on there ranges now,as you’ll know we don’t get the same quantity’s and variety of ammo you have in the states,and rubbish ammo is a fortune here let alone any quality ammo

 

[Feniks Technologies]

Ladder to light pressure
Back off a bit
Do a no-pressure-signs ladder
Find a flat spot
Shoot for groups
If you like the groups ... shoot at distance
Be happy ... you've succeeded in Load Development 101 !!!

Too much machination on this forum can drive you crazy. I know ... I am.

If you’re talking about actual velocity flat spots, that’s wasting components.

 

[b6graham]

Does this mean I shouldn’t bother with these results? Or that it looks promising? I’ve jumped down this rabbit hole and now I’m lost in the warren lmao

the results show that you're below pressure. and have a charge that has shot some small enough groups at 100y to most likely work at distance

i've moved away from most 'normal' load development like OCW and ladder tests

load up ammo to find 'pressure'
figure out velocity per charge weight
pick the speed i want that's a bit below pressure
start at roughly .060 off the lands
confirm it shoots acceptable groups at 100y, 600y
be done/stop wasting components