Velocity nodes and ladder tests

[VenatusDominus]

Two fascinating articles regarding load development, the standard "ladder test" approach, the "Satterlee" approach and velocity nodes. The first is a shorter and less technical article. Both have short summaries at the end if don't want or have the time to read them in their entirety.

https://storage.googleapis.com/wzukusers/user-33607572/documents/627aa957424246239bb5fe1bbb1204bf/Load%20Development%20v2.pdf

https://storage.googleapis.com/wzukusers/user-33607572/documents/112e3750a0794ba8a1c40781675ee21b/The%20Tyranny%20of%20Statistics%20Revisited.pdf

 

[Phil Rizzo]

The process can be as lengthy and technical as a man wishes.
Or a helluva lot simpler, just preference.

 

[RegionRat]

TLDR: The "velocity flat spots" evaporate once enough samples are shot.
Watch the targets first Grasshopper, then the chrono.....

 

[stazmania]

TLDR: The "velocity flat spots" evaporate once enough samples are shot.
Watch the targets first Grasshopper, then the chrono.....

View attachment 611429

looks like a node just over 60.0 and again just past 61.0 It would be interesting to know the quality of the rifle, components and the shooters credentials, as well as what the target showed "optimal charge weight" style. I haven't looked at the two links in the OP but I will. Fun stuff.

 

[BrentM]

I've adopted the Satterlee method for a short cut of sorts. I do believe it has plenty of merits to be a viable method but it's not the only method. Pick your own poison I suppose.

I think the key is to identify a place to start that gives you the best chance of finding an acceptable load for your needs/desires in the least amoutn of wasted components. This method seems to get you going fairly quickly. The second step of the process generally gets you zoned in on an area to tune. The third step seems to be the issue for most. Is it subtle or is it obvious? Monitoring FPS deviation and accuracy go hand in for me. I desire low sd and tight groups that have the best chance of being repeatable. I have had low sd and mediocre groups and I have high sd and tight groups.

 

[Beluebow]

Some load development process's are better than others IMO. A guy/gal has to find what works for their program. I'm a ladder test at distance guy.

 

[fta0303]

Two fascinating articles regarding load development, the standard "ladder test" approach, the "Satterlee" approach and velocity nodes. The first is a shorter and less technical article. Both have short summaries at the end if don't want or have the time to read them in their entirety.

https://storage.googleapis.com/wzukusers/user-33607572/documents/627aa957424246239bb5fe1bbb1204bf/Load%20Development%20v2.pdf

https://storage.googleapis.com/wzukusers/user-33607572/documents/112e3750a0794ba8a1c40781675ee21b/The%20Tyranny%20of%20Statistics%20Revisited.pdf

Interesting articles. One point that emerges is simplistic: measure what you care about directly - use the actual bullet on-target displacements from point of aim, not something else. The other is that number of samples matters - you have to take enough to establish the real variability of what you're measuring. Five shot strings are better than three shot strings.

Probably not very relevant in this forum: given that many hunters actually don't sight in their rifle before going afield, its important to stress that 3 shot strings are far better than no shots!

While hunting more than one or two shots is unlikely. It would be interesting to know the variability of single shots fired from cold rifles. Tedious to test, for sure. What you care about as a hunter is how accurate that first shot will be. Might that be different than you expect based on your careful laod development? When all is said and done, measure what you care about.

 

[RegionRat]

I've adopted the Satterlee method for a short cut of sorts. I do believe it has plenty of merits to be a viable method but it's not the only method. Pick your own poison I suppose.

See if you still think so after you read those articles in the links above.

If you found a charge weight using The Satterlee Method and you are happy, then it doesn't matter.

What we are telling you is you got lucky and the method has only a weak statistical chance of showing you an optimum. That method isn't even a very good "short cut" when you are just screwing on a copy of a known good match bbl.

However, for your sake and the sake of rookies who might fall into the trap created by The Satterlee Method, read those articles and circle back if you don't follow what the problem is with that method.