3 shot group vs ladder tests

[JoeInTucson]

Good Afternoon,
I grew up developing loads using the 3 shot group method.
Lately I have been noticing a lot of guys using the ladder method.
I have a chronograph and thought I would give it a go.
So what you are looking for is a place where the velocity does not change with charge weight, correct? So how much do you increment your powder charge for each step on the ladder typically? So from that I could assume that POA does not matter all that much?
Thanks

 

[ShtrRdy]

That approach was a fad a couple years ago. These days people don't put much faith in that method. I would stick with the 3-shot groups of various powder charges.

I will add that after I have come up with a load that seems to be a 'sweet spot' sometimes i have noticed the velocity to be quite similar over a few tenths of powder charge weight. It doesn't happen very often but it's possible.

 

[Deputy819]

I do BOTH, actually…..depending on what the rifle will be used for. If I’m working on a load that will NEED to be shot out to 500 yards…I’ll do a ladder test at 500 yards. If it’s a shorter range rifle/load then 3-shot groups at 100 and 200 yards works just fine. When in ladder mode I’ll increase in .2 increments and I’m more concerned with where each charge weight lands in relation to each other than I am with it’s relation to the “bullseye” or target spot.

 

[JFrank]

So from that I could assume that POA does not matter all that much?

POI is all that matters.

 

[Straightshooter1]

Good Afternoon,
I grew up developing loads using the 3 shot group method.
Lately I have been noticing a lot of guys using the ladder method.
I have a chronograph and thought I would give it a go.
So what you are looking for is a place where the velocity does not change with charge weight, correct? So how much do you increment your powder charge for each step on the ladder typically? So from that I could assume that POA does not matter all that much?
Thanks

The best ladder test is one where you're trying to find the maximum charge weight for a powder in your particular gun (like you don't use charges at or above that which is giving you pressure signs). Otherwise, velocity ladders don't tell anything as to what is a good load. The more you shoot of each load in the ladder, the more the results are a linear line. This has been shown many times over. Here's an example from Bryan Litz's book where he ran a test of 5 laders:

 

[RegionRat]

So what you are looking for is a place where the velocity does not change with charge weight, correct?

No. Velocity flat spots have been a great selling tool for chronographs but are not a valid load development method.

So from that I could assume that POA does not matter all that much?

This should be obvious to you once someone has warned you that the Satterlee 10 Shot Ladder Method was a mistake. I realize there are literally dozens of YT videos that front page headlined the method, but the retraction was in fine print on page 69.

In fact, the opposite is true, where you don't even really have to use a chronograph, but you do study the shot impact.

While there is nothing wrong with running a chrono in parallel to watch the charge-speed relationship, it isn't how you find an advantageous load.

Study the target, not the chrono.

 

[LVLAaron]

The best ladder test is one where you're trying to find the maximum charge weight for a powder in your particular gun (like you don't use charges at or above that which is giving you pressure signs). Otherwise, velocity ladders don't tell anything as to what is a good load. The more you shoot of each load in the ladder, the more the results are a linear line. This has been shown many times over. Here's an example from Bryan Litz's book where he ran a test of 5 laders:

View attachment 1673313

I've shot a lot of ladders for load dev. I've seen a lot of other peoples ladders. None look like that. They look more like this:



I picked 44.5 from that ladder and went on to seating depth. I know, I know, it's a trash method and doesn't work. But it does. At least for the disciplines I participate in.

 

[Straightshooter1]

I've shot a lot of ladders for load dev. I've seen a lot of other peoples ladders. None look like that. They look more like this:

View attachment 1673339

I picked 44.5 from that ladder and went on to seating depth. I know, I know, it's a trash method and doesn't work. But it does. At least for the disciplines I participate in.

Hmmm??? Well, if it floats your boat, then. . . . . Did you every try repeating that particular test of 3 ladders (or any of the tests) to see if it's repeatable?

I tried it once and it didn't work for me, so just focused on what the targets tell me.

Here's that raw data for those graphs that Litz published in his book (Volume III of Modern Advancement In Long Range Shooting):

 

[LVLAaron]

It works for me. I don't think Litz shoots like "we do" - I lost a lot of faith when he did his tuner test. Maybe it's how I hold the gun, maybe he uses a ransom rest, I don't know...

 

[Straightshooter1]

It works for me. I don't think Litz shoots like "we do" - I lost a lot of faith when he did his tuner test. Maybe it's how I hold the gun, maybe he uses a ransom rest, I don't know...

I know what you mean about the tuner test. I was surprised and disappointed in how he did that testing.

LOL . . . yeah, apparently you gotta hold the gun just right!

 

[kyotekiller25]

I like to use a combination of both. I usually do a ladder at 300 yards, find the max charge, look for a few shots that cluster together, then work around those charges doing 3 or 5 shot groups. Then I'll do a seating depth test after finding the charge. It seems to work ok for what I'm doing.

 

[CharlieNC]

A proper three shot ladder on a target should show a stable poi node, with corresponding improved shot dispersion ( group size and/or vertical spread ) at the node.

 

[seymour fish]

Good Afternoon,
I grew up developing loads using the 3 shot group method.
Lately I have been noticing a lot of guys using the ladder method.
I have a chronograph and thought I would give it a go.
So what you are looking for is a place where the velocity does not change with charge weight, correct? So how much do you increment your powder charge for each step on the ladder typically? So from that I could assume that POA does not matter all that much?
Thanks

Lately ?

 

[searcher]

The target alone shows what is good in accuracy. The chrono shows what the velocity of that load is, at what velocity the load starts off well and ends well - very helpful when knowing the powder leeway one has to tune in conditions. While one may find several "equally" accurate targets with various powders, for example, the better, most useable load of equal accuracy if most often found with the chronograph. After developing countless loads for over 50 years, I won't buy into finding an accurate load with the chronograph alone. I would go so far as to say that is crazy talk. But they both are very important....

 

[HandgunHTR]

The method that I use is probably what most would consider "a waste of components" but it works for me and I have come up with some pretty accurate loads in many rifles.

The first thing I do is load up 10-15 rounds, each with a bit more powder so that I can "find pressure" for my gun. Premium brass tends to hide the "normal" pressure signs pretty good (ejector marks, bolt lift, etc.) so a flat spot in the velocity is a pretty good indicator that I am there.

Once that is established, I load 5 rounds of varying charges from .3-.5 grains apart from one another, starting at just below the charge where I have pressure and going down from there. I usually do 4 groups, but sometimes I do 6. I shoot those at 300 yards. What I usually find is that 2 of those groups are better than the others. I then load up another 4 groups of 5 shots with tighter powder increments to find the "sweet spot". If I need even better, I then mess with seating depths, but for what I do, most of the time I don't mess with it.
Once I think I have the right load, I load up 20 of those and fire four 5-shot groups to confirm.

 

[Steve Donlon]

For me, I don't trust a ladder test. I like a 5 shot group because I'm not an expert shot, I am a sharpshooter. And I have seen bullets that are not great at 100 yards but are at 300 plus yards. You need to know your skill level to rely on the method you choose.

 

[K22]

It's a hobby and if you like to experiment go for it. You can make this hobby as complicated as you desire.

For me, I need a system: ammo, rifle, scope that will deliver a consistent POI because in hunting, you may not get a second shot. For me, the old 3 to 5 shot load testing development method has always worked. It gets to me to a qualified load quick with the least amount of component consumption.

After 50+ years of reloading and load development, I found that bullet selection* is the most critical component in seeking the precision grade accuracy I need for varmint (small critter) hunting. Powders are also important but if I find a bullet the rifle likes, usually there are several suitable powders that will produce similar results.

Load development has never been a limiting factor for me, it's been dealing with wind, mirage, and the low to high temperature ranges that I often encounter in the field. Shooter skills also play a major role in successful performance, a topic most shy away from because you can buy that, you have to earn it with dedicated practice.

* The problem in finding the best bullet becomes having to buy a box 50 or 100 bullets then finding out that they won't work well. When I was more active and had more fellow shooter friends (most have passed away or are no longer active), we would share a box of bullets for testing which helped keep the costs down. Something to consider.

 

[JoeInTucson]

Lots of good info here, thanks!
Seems like maybe sticking with what has worked for me for a long time is what I will continue with. Always thought the ladder technique had some assumptions in it……

 

[ISS]

Group size is my final arbiter. But I chronograph each round as well, since I am first and foremost a Rockchuck shooter at extended yardages. I have to have both. Hopefully they pair up.

 

[Varminterror]

So what you are looking for is a place where the velocity does not change with charge weight, correct?

This has been thoroughly debunked as pseudoscience.

Alternatively, it is better to realize that flat spots are anomalous and we'd rather see a linear relationship between increasing charge weight and increasing velocity.