Progressive Rifling and Velocity

[Snowdog]

Quick question: did the progressive rifling found in old cap and balls such as the 1858 Remington affect velocity at all?

 

[mec]

Tend to doubt it but there's really no way to know for certain without shooting an original or deeming the pietta -made progressive rifled target arms to be the equivalent of the originals. There are really too many variables- the performance of original powder and the different dimensions of the revolvers would probably be more important than the twist.

Jim Taylor, a writer with New Gun Week and others found that original remingtons had .452 chamber throats. Current Uberti's are usually 440" while piettas seem to run even smaller at .448-49. One writer reported very small groups with his gain twist pietta 58 target model the the difference in what he reported and what I get with my uberti replicas is not something I would be able to judge with my own bench rest shooting.

 

[unspellable]

Gain twist

I would expect any difference in velocity to be small enough to be obscured by all the other variables.

On the other hand, I wonder if it would be an accuracy advantage in a cap & ball revolver. The ball builds up a good speed before it hits the rifling and has a relatively small bearing area in the rifling. Starting the spin gradually might be easier on it. Does any one know if there is any problem with a ball skipping the rifling in a revolver? Might have something to do with every one reporting better accuracy in modern cap & ball revolvers with less than full house loads.

Are there any theories on why some of the old timers had gain twist?