I'm confused! Many good shooters "throw and go" -- others want to weigh each load. Regarding Gene's statement above, what about when two of the 10-percenters create a .6 grain spread from the others? Also, I've read about many folks doing ladder testing in .3 grain increments. What's accomplished with such testing if your loads have a reasonable likelihood of a built-in error of +/- .3 grain, or, as Hal suggests, bullets will go in the same hole with a rather large spread? Also, I've read Gene's comments about "we can't be more than .6 grains in either direction out to tune!" What that says to me is that +/-.3 grains can represent the difference between in-tune and not in-tune -- which seems inconsistent with his statement above.
So, the question (assuming a good barrel and a good shooter): How much spread in ALL of the charges is acceptable to have confidence in your load?
You need to refine your question.....a lot. As it's stands it's not answerable on any clear terms.
With ANY factory rifle on the planet, this whole discussion is wasted.
With any short-range BR rifle capable of winning, this discussion is wasted
With ANY 1000yd rifle capable of winning, if you're not lissenin' you're losin'
At 600yd BR the jury's still out whether or not compensatory tuning is effective.....and without a deep understanding of compensatory tuning (read Gene Begg's, again. And again) this discussion is wasted......
In short, this entire issue of weighing charges is only relevant to that tiny percentage of shooters on this planet who WIN SCOPED BR MATCHES at ranges beyond 500yds....
That's scoped Bench Rest Matches. Nobody else can even see the difference, unless you're a girl. Maiden name Gallagher....
That doesn't change the fact that since I KNOW the results I will weigh anything from hunting to target, open sights or optics for long range. Since I KNOW that I can and do get single digit ES with weighed charges and I KNOW that I cannot get under 40fps ES with thrown charges, I choose to weigh a lot of loads. I weigh individual charges on hunting loads for the comfort of knowing that I can shoot a water table at any yardage.
But for 6PPC's and 30BR's shooting 100-200yds it's irrelevant.
And for normal people who don't know a water table from an end table, people who talk in "moa" and three-shot "groups"......it don't mean squat.