No - you must shoot groups. Pick a powder/bullet combo based on what works for others with similar rifles and load up at least 10 rounds per charge weight. Then shoot five shot groups either prone or from a bench, but using a solid rest. Do this at 100 or maybe 200 yards, preferably in calm conditions. Measure the groups. There are no short cuts.
Ladder tests are interesting in that they can tell you if a load is going to be sensitive to powder charge, but they suffer from three problems. One- they are statistically inadequate. One shot per charge tells you very little unless the distance between the impacts is much greater than the accuracy potential of the rifle. This is often the case; you wind up shooting something that looks good, but is in actuality just random noise. Second, they tell you nothing about the accuracy of the load. You can get a pretty insensitive load that won't shoot well and it doesn't help you much. Third, wind is a problem at distances, and wind will cause vertical deflection, which further confuses things. The bottom line is that they're not terribly useful.
I have to disagree with you sir.
1) What is statistically inaccurate about a ladder test? What statistics can you bring to the table that disprove the ladder test?? A load will always be sensitive to a powder charge, its when you get close to a node that the charge can seem to be insensitive. That's why the ladder test will show a "group".
2)One shot per charge tells you quite a bit as far as where the node is (assuming the nut behind the bolt is capable). The reason we do this is so when we find the node, we can excuse a little over or under charge or variations in powder temp or whatnot, and not see it as much at distance. Also why we do it at 300 yards or preferably longer is because the differences show up better. There is no "random noise" here.
3)This tells you the very foundation on the accuracy of the load. What is accuracy? Consistency! What is consistency? Doing the same thing over and over the exact same way. In handloading, we strive to make the bullet come out of the tube at the exact same speed and the exact same.....BARREL NODE (obviously other principles as well). If you manage to find the barrel node, you can find a spot in the harmonic pattern where for a fraction of a second, the barrel "pauses" its vibration, and therefore we can use that consistent node, in order to achieve consistency.
4) Wind can cause vertical deflection, HOWEVER, do you really see the effects of it at 500 yards or less? Look at the OPs ladder results, that's 10mph with 15mph gusts at 500 along with rounds coming out at different integers of the harmonic sequence. Not a whole lot of later dispersion, huh? Talking about vertical wind deflection in this is irrelevant.
Bottom line: they are very helpful. Of course, this is better refined when you do it again with smaller powder increments and farther distance.
After you get the initial info from that, yes then we can play around with jam or jump, neck tension and all the other parameter, but with the ladder test, you get a very solid baseline and you have used less rounds than shooting groups.
