load testing are there newer more efficient methods now?

[Alex Wheeler]

Well, this topic comes up pretty often. I can say as someone who was competitive in the agg, AND has tried other methods, that 1k ladders provide the most solid data and more of it than other method. Now they dont work for everyone. It takes skill to perform them and you have to have good conditions as well. One thing I believe in is positive compensation, and I know of no other way to pin point its location for 1k grouping other than a 1k ladder. I have and keep trying but cant do it with consistency. I love my short range buddies, but I think its something you need to see in person to believe it. All the best aggers I know across the country that can do it year after year, barrel after barrel, tune in this manner. That does not mean you cant make other methods work, guys do it. But its a different way of tuning, and I dont feel that its going to put you in the right spot as quickly and consistently barrel after barrel.

 

[dcali]

A few things that really help:

loading at the range - keeps you from loading up rounds you know won’t work. This is a huge cost saver. At the very least seat the bullets long and use an arbor die at the range to fine tune the seating depth.

Five shot groups: this is the most statistically efficient group size. Unless you can get a way with software that measures every shot’s distance from the group center, which is even better. Tiny groups make this difficult, but that is a good problem to have. More than 5 shots per group is wasting ammunition. Two five-shot groups gives more confidence than one ten-shot group.

Skip the ladder and leave the chronograph at home. Nobody agrees with me on this but a ladder is all but useless unless it is a) repeated and b) it finds a node that actually shoots well. Just because it’s a ladder node doesn’t mean it’s a small group. Same goes for chasing “flat spots” for charge weights. Everyone swears they exist but nobody can show me statistically valid evidence.

Pick your variables carefully. Settle on a primer, bullet and powder. Don’t test these. just pick them based on advice. Then find a combination of charge and seating depth. These are not independent variables - there is usually at least a little interacrion between the two. So you can’t test them one at a time without risking winding up with a local optimum (that is, a good load but not the best possible).

Benchrest is different. benchrest Shooters get into more detail because they’ve been testing so much stuff with basically the same rifles that they can afford to get lost in obscure variables. The rest of us can’t. We don’t have the “flight heritage” as they say in the aerospace business. They can skip this whole post, actually.

You’re not going to be happy with the statistical confidence in your load testing. But that doesn’t mean you can ignore it. There is no substitute for rounds down range. If I told you to shoot one shot groups you’d laugh. That a exactly what you’re doing with a ladder test. It’s not enough by itself.

Chasing a load with just a few rounds is wasting a few rounds at best and lying to yourself at worst. Treat load development like practice if that’s what you need to tell yourself. Nobody complains about wasting practice rounds.

Don’t test if it’s windy. Do bring wind flags because there’s always a little wind. Shoot at 100 yards.

 

[Bart B.]

Five shot groups: this is the most statistically efficient group size.

If one 5-shot group is fired, how much larger, statistically, do you think the biggest one be from the average size of several than the smallest one, 95% of the time?

Some say about 160% of average to about 65% of average. If average is 1 MOA, group's will be from .65 MOA to 1.6 MOA.

 

[retired]

well its good that it is your opinion and not followed by most accuracy based shooters.
just one more person to ignore.
in shooting small groups if the second shot is not touching the first, do not shoot the third..the group will not get smaller, just wasting ammo...so much for always shooting 5.
if loading for long range do not shoot at 100 if 200 is available, do not shoot at 200 if 300 is available.
( see alex's post)
i get the feeling you do not compete in br

A few things that really help:

loading at the range - keeps you from loading up rounds you know won’t work. This is a huge cost saver. At the very least seat the bullets long and use an arbor die at the range to fine tune the seating depth.

Five shot groups: this is the most statistically efficient group size. Unless you can get a way with software that measures every shot’s distance from the group center, which is even better. Tiny groups make this difficult, but that is a good problem to have. More than 5 shots per group is wasting ammunition. Two five-shot groups gives more confidence than one ten-shot group.

Skip the ladder and leave the chronograph at home. Nobody agrees with me on this but a ladder is all but useless unless it is a) repeated and b) it finds a node that actually shoots well. Just because it’s a ladder node doesn’t mean it’s a small group. Same goes for chasing “flat spots” for charge weights. Everyone swears they exist but nobody can show me statistically valid evidence.

Pick your variables carefully. Settle on a primer, bullet and powder. Don’t test these. just pick them based on advice. Then find a combination of charge and seating depth. These are not independent variables - there is usually at least a little interacrion between the two. So you can’t test them one at a time without risking winding up with a local optimum (that is, a good load but not the best possible).

Benchrest is different. benchrest Shooters get into more detail because they’ve been testing so much stuff with basically the same rifles that they can afford to get lost in obscure variables. The rest of us can’t. We don’t have the “flight heritage” as they say in the aerospace business. They can skip this whole post, actually.

You’re not going to be happy with the statistical confidence in your load testing. But that doesn’t mean you can ignore it. There is no substitute for rounds down range. If I told you to shoot one shot groups you’d laugh. That a exactly what you’re doing with a ladder test. It’s not enough by itself.

Chasing a load with just a few rounds is wasting a few rounds at best and lying to yourself at worst. Treat load development like practice if that’s what you need to tell yourself. Nobody complains about wasting practice rounds.

Don’t test if it’s windy. Do bring wind flags because there’s always a little wind. Shoot at 100 yards.

 

[jimmymac]

The Boyer method works fine for me and what I do. I'm not shooting 1000 yards. I'm shooting 100 to 300.

I like to go with a 4x4 pattern for the initial test. That requires 48 loaded rounds and a handful of fouling shots to complete the test. Over the course of fire a pattern will develop and show preferences for powder charge and seating depth. Once that is established the testing does not end there though. Fine tuning of seating depth and powder charge in and around the best results from the original test target is needed to arrive at an optimal powder charge window and seating depth. By the time it's said and done, I may be 80 to 100 rounds into it, but at that point I'm pretty much done because I should have a clear picture of what's going on. There may be more efficient methods but the above should have you shooting bugholes if your gun and you are up to the task.

The big deal with this test is to shoot it in good conditions and use wind flags. You better be shooting off a good bench and have a solid setup in the bags too or the results won't mean much. Of course, that could be said of any test. Your results are only as good as the weakest link in your system.

 

[dcali]

well its good that it is your opinion and not followed by most accuracy based shooters.
just one more person to ignore.
in shooting small groups if the second shot is not touching the first, do not shoot the third..the group will not get smaller, just wasting ammo...so much for always shooting 5.
if loading for long range do not shoot at 100 if 200 is available, do not shoot at 200 if 300 is available.
( see alex's post)
i get the feeling you do not compete in br

Did you even read the post?

 

[dcali]

If one 5-shot group is fired, how much larger, statistically, do you think the biggest one be from the average size of several than the smallest one, 95% of the time?

Some say about 160% of average to about 65% of average. If average is 1 MOA, group's will be from .65 MOA to 1.6 MOA.

My stats are a little rusty, but if I recall correctly, the 95% confidence level for a 5 shot group is roughly 1.5x the group size, so that 160% number sounds about right to me. More importantly, and what a lot of people don't get because it's not very intuitive is that 3 5-shot groups gives a higher confidence than 5 3-shot groups.

 

[dcali]

The Boyer method works fine for me and what I do. I'm not shooting 1000 yards. I'm shooting 100 to 300.

I like to go with a 4x4 pattern for the initial test. That requires 48 loaded rounds and a handful of fouling shots to complete the test. Over the course of fire a pattern will develop and show preferences for powder charge and seating depth. Once that is established the testing does not end there though. Fine tuning of seating depth and powder charge in and around the best results from the original test target is needed to arrive at an optimal powder charge window and seating depth. By the time it's said and done, I may be 80 to 100 rounds into it, but at that point I'm pretty much done because I should have a clear picture of what's going on. There may be more efficient methods but the above should have you shooting bugholes if your gun and you are up to the task.

The big deal with this test is to shoot it in good conditions and use wind flags. You better be shooting off a good bench and have a solid setup in the bags too or the results won't mean much. Of course, that could be said of any test. Your results are only as good as the weakest link in your system.

This is more or less what I do as well. It requires no interpretation (which is a sign that you're doing it wrong), and it is guaranteed to find the best load inside your grid. I don't think there is much that can be done to improve the efficiency other than tossing out sections fo the grid as you shoot due to unacceptable performance. Other "more efficient" methods may require fewer shots, but they offer far less confidence.

 

[memilanuk]

Seems like an appropriate place to throw this in...

 

[Bart B.]

More importantly, and what a lot of people don't get because it's not very intuitive is that 3 5-shot groups gives a higher confidence than 5 3-shot groups.

How about one 15-shot group's confidence?

 

[BCBRAD]

Yesterday I loaded 5 rounds.

It's a 6 Dasher light rifle (<10.5 lbs.) normally use 105gn Hornaday BTHP for practice and steel.

A 1000 yard competition is coming up so I switch to 105 Berger Hybrids.

I know that Varget is a little to 'fast' for this combination, progressive burn ends before peak pressure.

H4350 at 34.80 gn, models well, progressive burn stops at peak pressure and the load is on a node.

I will record the 5 velocities, make minor adjustment to the powder charge due to the burn rate (Ba) being a variable.

Predicted velocity is 2903 ft/s.

 

[dcali]

How about one 15-shot group's confidence?

The 15 shot group x about 1.25 (roughly) gives you 95% confidence.

If you mean how much worse is one 15 shot group than 3 five shot groups, then take a look here: http://bisonballistics.com/articles/optimal-group-size-for-rifles

That article is based on some data that contains some errors due to a smaller than optimal sample size in the original work. The general theory is sound, but the optimal group size is closer to 5 shots than 7 or 8, as is mentioned in the article. At some point I'll update it, but even with the old data, the trends are easy to see.

The link milanuk posted in post #29 provides a more thorough analysis (with vastly more data - it's where the 5 shot group recommendation comes from).

 

[Bart B.]

If you mean how much worse is one 15 shot group than 3 five shot groups, then take a look here: http://bisonballistics.com/articles/optimal-group-size-for-rifles

Best info I've seen on statistical stuff on shots per test group. Here's the best I glean from that article:

A few three shot groups is just not going to get you any confidence in your rifle's accuracy.

In no situation should you ever use 3-shot groups to get an indication of accuracy. It's just not an efficient way to spend your money or your time.

 

[oldroper]

Best info I've seen on statistical stuff on shots per test group. Here's the best I glean from that article:

Bart, Why don't you post target (real target) on groups that you have shot! You send one to Kreiger.

 

[dcali]

Best info I've seen on statistical stuff on shots per test group. Here's the best I glean from that article:

The link Monte posted was done by more competent people than me. It's a little harder to decipher (more technical), but take a good look through it - there's a lot of good info.

 

[Alex Wheeler]

None of us shoot one shot ladders. At least 3 per charge.

 

[retired]

then it is not a ladder it is group shooting.
nothing wrong with shooting three shot groups to find a load, but it NOT LADDER SHOOTING.

None of us shoot one shot ladders. At least 3 per charge.

 

[Nature Boy]

I'm just getting into F/TR (mid range, 300/500/600) and have incorporated the Cortina method into my load development. Per that method, I'll take the load that reveals itself as the most accurate, in both powder charge and seating depth at 100 yards, then shoot groups of 20 shots at 500 yards looking for consistency. This also gives me the opportunity to practice. I'll take that load to the match.

I was able to achieve mid range high master in my first 4 matches so I think it's working.

 

[Alex Wheeler]

then it is not a ladder it is group shooting.
nothing wrong with shooting three shot groups to find a load, but it NOT LADDER SHOOTING.

Its exactly the same other than we shoot 3 per charge instead of one.

 

[Ringostar]

then it is not a ladder it is group shooting.
nothing wrong with shooting three shot groups to find a load, but it NOT LADDER SHOOTING.

How about if you consider it three single shot ladders that are overlaid on top of each other? I see it the way Tom and Alex do it as confirmation.