Shots per charge before you trust a ladder's speed trend?

[2labs]

I keep seeing ladders with one shot per charge where the speed goes up and down as the charge goes up, so I built a made-up ladder to see how much of that is just normal shot-to-shot variation.

6.5 Creedmoor, 24 inch barrel, 140 gr ELD-M, H4350, CBTO 2.230, six charges in 0.3 gr steps (38.5 to 40.0 gr), 3 shots each, 100 yards. The numbers are made up but realistic. It is not a load recommendation, check your own manual.

The average speed climbs about 8 fps per step. The shot-to-shot SD inside a single charge is about 10 fps. So one step up is smaller than the variation within one charge.

I ran it through Loadscope, the program I make for Mac and Windows, so I'm biased. It scores velocity flat spot (5%), velocity SD (20%), mean radius (40%) and vertical dispersion (35%), and it picked 38.8 gr. It also said that at 3 shots a charge, 38.8 and 39.4 are too close to call, and suggested 10 rounds each to settle it. The Results screen is in the picture.

How many shots per charge do you shoot before you believe the speed trend? Do you add shots, or make the steps bigger?

Wrote up how many rounds a ladder needs here: https://loadscope.app/learn/how-many-sh ... harge.html

[Damo300]

Firstly....I'm a novice loader.
Been at it for about 3yrs.

I load up 3 shot groups like you are to start oout.

Then I step up to 5 shot groups when I'm working finer powder adjustments inside a specific powder weight...ie 38gr up to 39.3, and they'll step up in 0.2gr powder increments.

I'm only chasing hunting loads though. More so, cold bore shots. The other 4 that follow are just to get the average, but they're super accurate out to 300m, and 5 shots gives me a pretty good indication of ES and SD consistency.

Then I'll run a 10 shot group once I'm satisfied I have found a good load just to finish off and confirm accuracy.

Everyone does it different, and I love hearing, and learning more about loading.

[Wapiti]

Great work making a system like that 2Labs, as a tradie I'm humbled, I could have absolutely no patience to be able to lean how to do that.

Mate I just can't see how a programme can foresee or recommend the best "node" for an individual rifles barrel - we know two rifles off the assembly line one after another, most likely, perform totally differently with a given handload. Yes of course there are exceptions in both the tool and what it's fed - some concoctions shoot very across a big range of different rifle barrels - take the Federal Gold Medal Match 168gn .308 Match loading for example.
Handloaders tie themselves in knots trying to duplicate this concoction.

On the ladder test - and the "node" (what a wanky name) that firearms have hidden somewhere... my view is you just have to try it from a mechanical level. I.e. try it and shoot it, whilst changing nothing else. Otherwise it's a wank.

I've been handloading, no sh*t, for 45 years, and have never found the magic bullet.
There's SO MUCH more than 0.2gns of powder, there's the assembly of the components themselves absolutely consistently - hopefully members here realise from other posts that some gear NEVER delivers this. Without solving the inconsistency of the cheap gear first, the rest is a pipe dream. People are sold complete crap by "gun writers" that pound from urban computers to meet timing and sales expectations.
All the mechanics has to be solved first, and most never get that far.

I see it all the time, new people to all this do it for a few years and then are experts - as soon as someone recommends a definitive load and says "this is your answer" I realise I must remember to take everything else they say with a grain of salt.

What I want to know is, what is the "ladder test", why is it so regarded as the answer, how is it done, why are the incremental percentages of up/down 0.3 or 0.2gns gospel, and how is it done on a practical sense?
Why is it different from the man who tries say, 3 shots at a given powder charge, go up by 0.5gns and try that, all the while looking at the numbers too and look for these connections?
3-shot groups compared to 5 or 10... not a consideration for me. Someone who has been doing this for so long from a practical perspective is - the first shot, maye 2nd, the 3rd maybe if they don't group 5 never will.
For the bloke lying in the grass for that first shot, that's the one. Maybe number two, but 3... thats on the run. The rest is best left for those who like to burn powder.

As a bloke who does what I do, but buggers around with long range shooting as well and has kind of figured it out as far as a bloke like me can, tell me how this ladder test and the Gold at the end of the rainbow is found, other than by actual copper and nitrocellulose.
Mate I'm dead serious here, I'm genuinely interested.

[2labs]

Thanks Wapiti. It doesn't foresee anything. You still load and shoot every charge, same as you do now. The program just takes your chrono file and your target measurements and scores every charge the same way, so the pick comes from your own barrel, not someone else's load.

What you described, 3 shots at a charge and then going up while watching the numbers, is a ladder test. There's no magic step size. The question in my post was how many shots it takes before the speed trend actually means something.

Agreed on the gear too. If the reloads aren't consistent, no ladder will show you much.