Article proving that ladder tests don't work for load development

[Bobbygun]

Yeah but was that with a 50 shot group? If not, it's statistically invalid.

Dang! You would think I would know about statistical validity. I have a minor in Applied Mathematics which required several 400-level statistics courses for which Calculus was a prerequisite. I guess because I'm so old I used an abacus and a stone tablet, so it doesn't count.

 

[DizzyJ]

Dang! You would think I would know about statistical validity. I have a minor in Applied Mathematics which required several 400-level statistics courses for which Calculus was a prerequisite. I guess because I'm so old I used an abacus and a stone tablet, so it doesn't count.

According to the "experts" none of us know what we're doing.

Still waiting for the bench rest guys to give up working up a load…….

 

[Koda]

I haven't listened to the podcast but wonder if the Quinlan Neville study was meant for mass produced factory ammo... which would be more applicable to a company like Hornady.

 

[arakboss]

Has anybody here tried this method yet?

"It might seem that simply loading a 20-round batch of a first load sample is crazy and inefficient, but the results are the results. You're going to get a representative group size and velocity SD for the entire range of charge weights."

I am going to give it a go on my next range trip. I have a Savage 308 HB I started to break in years ago that will be my test rifle. I really have no idea what powder or bullets it will like. I will pick a standard type bullet (150gr fmj) and load up 5 different powders at mid level charge weight and 20rnds of each powder type.

I am going to shoot the groups at 50yds to help minimize shooter errors. It will be interesting to see if one powder stands out above the rest.

Edit: I am going to try 10 different powders, 20rnds each. It will probably take two range trips, unless I want to really heat up the barrel.

 

[Ben B.]

Has anybody here tried this method yet?

"It might seem that simply loading a 20-round batch of a first load sample is crazy and inefficient, but the results are the results. You're going to get a representative group size and velocity SD for the entire range of charge weights."

I am going to give it a go on my next range trip. I have a Savage 308 HB I started to break in years ago that will be my test rifle. I really have no idea what powder or bullets it will like. I will pick a standard type bullet (150gr fmj) and load up 5 different powders at mid level charge weight and 20rnds of each powder type.

I am going to shoot the groups at 50yds to help minimize shooter errors. It will be interesting to see if one powder stands out above the rest.

Edit: I am going to try 10 different powders, 20rnds each. It will probably take two range trips, unless I want to really heat up the barrel.

You are a rock and roll star, and my new reloading hero. Please post your results and observations.

 

[Koda]

I am going to shoot the groups at 50yds to help minimize shooter errors. It will be interesting to see if one powder stands out above the rest.

You actually want to see shooter errors when shooting for group size to rule them out. Otherwise you wont know which powder charge is optimal, close range group size will also minimise seeing the optimal charge weight. You need to shoot your test at least 100yds to find optimal charge weight.

 

[Bobbygun]

20rnds each

TWENTY? I thought at one point, folks were talking 100 rounds. You gotta pump those numbers up!

This study is gonna revolutionize reloading! Or maybe not. Haven't heard crickets about it, and folks are still doing ladder tests the way they always have. But hey, it impressed somebody along the way.

Save your time, money and powder for all that 10mm ammo you're gonna need for your new Rock.

 

[Spitpatch]

Regarding large "sample sizes", "number of shots for a valid group", etc.":

Most notable in "load work-up" (for hunters, especially) are the individual characteristics of the rifle itself, that affect its behavior toward any given load:

For example, the load that shows the most consistent velocities and best first-shot accuracy (delivery without fail to point of aim from a cold barrel) may indeed be a pretty crappy 7-10 shot grouping load.

IN THAT GUN.

So, do we disregard this load? What if the rifle is a Single Shot? What are the chances it will ever be shot 7-10 times at the same game animal? This may still be the best load if the variance the rifle demonstrates after the first shot is acceptable as compared to the predicted frequency of a multi-shot scenario.

Number of shots in a test group should be tailored to the gun's design and intended purpose.

Now, for those whose rifle's theater of operations is fixed and immovable and never changes, such as those who enjoy the sound of throwing rocks at a fry pan hanging from a string, over and over and over again from 800 yards, certainly a valid test group should approximate the number of rounds they intend to shoot in any given day.

 

[arakboss]

You actually want to see shooter errors when shooting for group size to rule them out. Otherwise you wont know which powder charge is optimal, close range group size will also minimise seeing the optimal charge weight. You need to shoot your test at least 100yds to find optimal charge weight.

Why not shoot at 300 yards?

 

[Koda]

Why not shoot at 300 yards?

Some people do, youll get 3x more clarity on accuracy "nodes".
The problem is it depends on how well one shoots, plus any inaccuracies in the rifle build, can add up and ruin the target data.
Its a judgement call, but generally 100yds is an ideal minimum thats practical for most. Your looking for the charge weight with the smallest group size. Very difficult to find at 50 yds.

 

[arakboss]

Some people do, youll get 3x more clarity on accuracy "nodes".
The problem is it depends on how well one shoots, plus any inaccuracies in the rifle build, can add up and ruin the target data.
Its a judgement call, but generally 100yds is an ideal minimum thats practical for most. Your looking for the charge weight with the smallest group size. Very difficult to find at 50 yds.

I have poor shooting skills, poor vision, cheap scope, etc. I figure my best chances at minimizing those elements and isolating powder influence on group size, is to shoot at a shorter distance. It seems unlikely a powder is going to shoot worse groups at 50 yards then it will at a 100yds but I have been wrong before.

 

[Koda]

I have poor shooting skills, poor vision, cheap scope, etc. I figure my best chances at minimizing those elements and isolating powder influence on group size, is to shoot at a shorter distance. It seems unlikely a powder is going to shoot worse groups at 50 yards then it will at a 100yds but I have been wrong before.

Powderr doesnt shoot worse or better from distance. Your comparing different powders group size.
You dont have to be the best shot, but you only have to be a consistent shot to find the best group size.... your just looking for the smallest group size to determine which powder is more consistent ( if all other things are equal).

Its hard to explain , but you will see group size better at 100yds than at 50. Its a matter of resolution....
A 10in group at 100yds will be 5inches at 50. But a 11 inch group will be easier to measure different than the 10 inch group at 100yds than a 5.5inch group will be at 50yds. (Exaggerated group size for clarity). It gets harder to measure this effect the smaller your group size.

 

[arakboss]

Powderr doesnt shoot worse or better from distance. Your comparing different powders group size.
You dont have to be the best shot, but you only have to be a consistent shot to find the best group size.... your just looking for the smallest group size to determine which powder is more consistent ( if all other things are equal).

Its hard to explain , but you will see group size better at 100yds than at 50. Its a matter of resolution....
A 10in group at 100yds will be 5inches at 50. But a 11 inch group will be easier to measure different than the 10 inch group at 100yds than a 5.5inch group will be at 50yds. (Exaggerated group size for clarity). It gets harder to measure this effect the smaller your group size.

Measuring a 20 shot group may prove difficult anyways. I get what your saying. If my groups are so tight that I have trouble determining which powder is better, I will be a happy camper. And if that happens I will move out to shooting at 100 yards for future testing. I doubt that will be the case but I can hope.

 

[Koda]

Measuring a 20 shot group may prove difficult anyways. I get what your saying. If my groups are so tight that I have trouble determining which powder is better, I will be a happy camper. And if that happens I will move out to shooting at 100 yards for future testing. I doubt that will be the case but I can hope.

Its the difference between group size your looking for, will be easier at 100 than 50 yds.

5 powders at 20rds each is a lot to test. Shooter fatigue may be a factor in group size as well as barrel fouling.

 

[arakboss]

Its the difference between group size your looking for, will be easier at 100 than 50 yds.

5 powders at 20rds each is a lot to test. Shooter fatigue may be a factor in group size as well as barrel fouling.

I was going to run some patches after each 20rnd group. Fatigue will be a bigger issue on 300WM and 7mm rem mag testing

 

[Koda]

I was going to run some patches after each 20rnd group. Fatigue will be a bigger issue on 300WM and 7mm rem mag testing

Wait...
5 powders, 20rds each....
Between two different cartridges?

 

[arakboss]

Wait...
5 powders, 20rds each....
Between two different cartridges?

I am doing one rifle at a time starting with a Savage 308. If this system really works (I have doubts), I will use it for all rifle testing.

 

[arakboss]

The reason I have doubts is from videos I've seen. Somebody will be ladder testing and have crappy groups, then a good group comes along, then more crappy groups. If you only test one charge weight that could be a charge weight the rifle didn't like.

 

[Spitpatch]

Wait...
5 powders, 20rds each....
Between two different cartridges?

That methodology of experimentation would require a record-keeping and organizational skill set which I do not possess.

 

[Koda]

If you only test one charge weight that could be a charge weight the rifle didn't like.

You just solved your whole experiment right there.