I did what you're doing for well over 2 decades. When I turned 70, I asked myself what the cumulative economics were saying to me, since whatever I did from this point on was sorta for the whole ball game. We'd all like to die with the most toys, but me, I don't really want to die with any saved rounds.
Also, I don't have the kind of money you're probably alluding to. My formative learning was largely driven by some very real funding limits. All that went before was a process of refinement, sharpening my methods to a finer point. For the present and the foreseeable future, every penny of my income derives either from SSI or VA Disability. In essence, what I'm really doing is channeling some of my Government's outlay to support better ballistics and marksmanship, by what I post here, and nowhere else.
I figure I do it once, the rightest way I can manage, and stick with what the larger samples were really telling me, aside from how much I had (maybe ) wasted with my less complete/thorough approach. Sorta holding my own feet to the fire. If I'm not sure a load is as good as I want it to be, the pound foolishness derives from all the loading I could be doing subsequent to finding the penny wisdom.
You're not wrong. Few of us are actually badly wrong, I'm just saying we're both right, depending on our point of view. From your point of view, you probably fabricate a fair number of rifles with largely identical barrels. Knowing, with some certainty, what loads those barrels prefer can be a large marketing edge. That knowledge is scalable, making the cost smaller proportionately. I'd actually be rather surprised if that wasn't something you'd already established.
Some (many) years ago, I coined a phrase, Optimal Charge Weight, but not in the sense it has since grown to mean.
My meaning was that some ammunition makers understood that many. many of the barrels they would be producing loadings for would be, for many intents and purposes, roughly identical in length, twist, and profile, especially hunting barrels. So they could fabricate a more generic (OCW?) loading in large quantities, and reap the benefits of scale, primarily in repeat sales.. This is, I believe, what makes FGMM so hard to beat, and Core-Lokt so popular with hunters. It's all really about the testing; pay me now, or pay me later. This is the less obvious meaning contained in my signature line.
When I give up some points by arbitrarily limiting my basic premises, I am forced to wring the most truth from those few remaining basic premises I choose to test upon. In reality, 6 sets of 25 rounds, tested in a single process, is only 150 rounds overall.
...And some trends are going to appear by around the time the third set of groups of 5 are done, which can reduce the number of shots actually required. Those saved shots also have a dividend in bore life. Also, I cannot predict where the sweet spot will alight, so I am perforce constrained to have a full set of each increment onhand when testing begins. Meanwhile, I can pull down any saved rounds with the RCBS collet puller, and the components can be reassembled to the derived load spec and serve ably for sighter/fouler rounds.
Or, maybe the test is getting close enough to reload those potential sighter/foulers into more finely divided increments; or maybe they're defining a broader sweet spot, which can also be useful info, like for a secondary round of testing at greater distance.. So in reality, I still have maybe 350 virgin bullets from that purchase lot, and maybe 25-50 of the saved rounds (or not) have been converted into sighter fouler rounds, so (perhaps) I'm really not being so wasteful after all.
The point is that testing need not be driven by hard and true limits; and testing, done more thoroughly, need not be a waste of anything. When we limit our testing, we subsequently limit our possibilities.
Greg