1. Look at the Erhard Wolf book on Jaeger rifles. A few of the later rifles show more pronounced heals. Yes... they're still pretty flat... but it shows a beginning of the evolution to curved butt plates. These correspond to similar styles used in America at the same time (roughly 1770's).
2. The American rifle tradition evolved with German immigrants.
3. Because American gunsmiths were less restrained by more formal styles, I believe they were more free to change and evolve... for better or for worse... and there doesn't need to be a logical, or scientific, or engineering, reason for it.
4. "Calibers got smaller because all the big game was gone". I don't believe that myth. I think it was partly due to economics. Small gun... less powder and lead to buy... less expensive. What I've read leads me to believe the smaller calibers were starting to be used it poorer areas first and moved out from there.
5. You're speaking too much in absolutes... "clearly"... not really... "you have to agree"... no I don't.
6. "More art than science"... you're looking too hard at cause and effect. Not everything is done for logical reasons. It reminds me of a line from a TV show... "it doesn't always have to make sense... like plus size bikinis". Barrel length and weight may have nothing to do with the shape of the butt plate.
7. I've read far more period journal references to shooting from a rest than I have about standing square or angled in relation to the target.
8. Some competitive shooting matches may have established positions that you were expected to use. I believe these evolved from formal matches in Germany. Back county matches probably didn't. They could shoot however they wanted.
9. There are period paintings of shooting matches. A good one is "Shooting for the Beef" by George Caleb Bingham (ca. 1850). It shows a back country shooting match.
10. Crescent buttplates may be bad for some shooting positions... but some shooting positions are just plain bad in themselves. Remember all those drawings of match shooters from the 19th century in contorted positions? In hindsight they don't make much sense either... but they did it.
What does this tell you about the shape of a buttplate?
Sometimes we just have to accept what "is"... or in this case "was". There doesn't need to be an explanation. The same holds true for ourselves. Lets accept ourselves for who we are and accept the longrifle for what it is.
Most if not all of what you quoted didn’t come from me. For whatever reason, people who seem best-informed do not entirely accept any of the standard conjecture about lengthened barrels and smaller calibers. I have nothing to contribute to that discussion, except perhaps the observation that 250 years ago chronographs were exceeding scarce. If velocity were the reason for longer barrels, it might not matter if there was no practical advantage. Perhaps they believed there was an advantage. Bullet drop would have been a clue but they weren’t all Galileo. Neither are modern shooters when you look at the difference between their perception of power vs real difference.
Re military rifles, we have to consider they must be shot from all positions, and crescent plates are poor, almost impossible for that. Military rifles also have to work for every skill level. From what I see, many modern shooters try to mount crescents to the shoulder. If you had 10,000 recruits in 1812, you’d have the same problem or worse. So of course they were flat.
I don’t insist that historians explain the crescent plate in practical terms, or any other terms. I do believe, as a historian, there should exist at least some published discussion and research on the subject. From what I’m hearing, nobody has really looked into it. Sometimes research means “I couldn’t find enough direct evidence for a firm conclusion.” I wouldn’t expect to find much direct evidence. But lack of direct evidence is, in its own way, information. It means we have to adjust our expectations, and find different angles of inquiry. E.g. someone could hypothetically tabulate the percentage of surviving crescent vs flat buttplates over time, plot them geographically, and have a starting point. It’s not necessary to have a letter from Crockett saying “I hate those things, they hurt.”
I never, I think, asserted any conjecture as undeniable fact *except* that people were not shooting actual crescent plates from the shoulder pocket. I think it is undeniable that people were not shooting from the shoulder pocket with crescent plates that became extremely common, and very deep. I think that is a reasonable assumption. I think nobody can reasonably argue that crescent buttplates as they evolved to be deep were mounted to the shoulder pocket.
And I think the corollary, almost as reasonable assumption, is that they started shooting off the arm. And it follows that they presumably turned their bodies near 90deg to the target, because if you point a gun straight forward from your upper bicep, facing the target, your neck is not long enough to use the sights.
Which is all physical evidence that they *might* have started using rifles differently than when the plates were flat. I see people obsessing over “architecture”, cheekrests, carved motifs, minor differences in trigger guards, all kinds of wholly cosmetic features. At the same time the rifle became longer, the plate became so deeply concave, double set triggers became common. This is all telling us something and saying, “they just liked the way it looked” doesn’t cut it.
I’ve done my share of dense historical research and am not taking this up. But at this point in time I expected people would have recognized it as being significant enough to look for evidence.