Progressive DEPTH in original Spencer rifling?

[Snakeeater]

You said that one expert said that Sharps (presumably Christopher Sharps) "knew" that progressive depth rifling didn't help the ring-tail bullet, he (the expert) knew this how? Indeed, I would find this hard to believe considering that Christian Sharps severed all his ties with the Sharps Rifle Manufacturing Company at Hartford in 1853, so the inventor would have had little to say about whether the company continued to use progressive rifling afterwards. While certainly progressive rifling assists hollow-based projectiles, even the small bore Enfields in .453 as well as the Kerr rifle utilized it, though the Kerr had its own unique twist rifling which began as straight rifling before changing to a gain twist. But even solid base projectiles tend to compress and obturate in the bore, otherwise there would be no need to rifle the bore at all. Some of the early Whitworth bullets were solid base conicals, some were even obloid at both ends, yet, even these still managed to obturate and exit the bore as a hexagonal-shaped projectile. The Lancaster oval-bore, though not as accurate at long range as the Whitworth, was still more accurate than the regulation Long Enfield, and was capable of striking a man at ranges up to 1200 yards when the regulation Long Enfield petered out at 600.

[Fox Creek Kid]

Don't fall prey to the mental "trap" that many do today whereas the gunmakers of the 19th century were akin to mystical Japanese senseis. They were learning as they went and they did not have near the scientific eqpmt. or knowledge that we have today to quickly discern if a theory is valid or total BS. Remington was playing with rifling twists for years in their RB models. Sharps was experimenting as well as was Winchester. The bottom line is that BP is a technological dead end not unlike the horse and a lot of the knowledge was worthless when smokeless came onto the scene & cupro nickel jackets.