Michael, I think the flats predate receiver-built cartridge rifles. If so, If they originated on muzzleloaders (and for sure they were put on muzzleloaders), then I can't see how the flats purpose would work that way. Breech plugs just don't require them and, in fact, they get in the way a lot.

I feel their purpose was just cosmetic, and any structural effects were just coincidental.

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BrentD, (Professor - just for Stan)
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