|The Civil War Artillery page (http://www.civilwarartillery.com/mainpage.htm) does mention what type of sabot was used with each projectile type, if any. The second sub-patern Blakely (http://www.civilwarartillery.com/hap/page61.htm), used in heavy rifled guns, lists no sabot was was used, possibly because of the flanges on the side of the shell. But then the Pattison projectile (http://www.civilwarartillery.com/projectiles/rifled/FAOIIIa126.htm), used in field rifles, also has the flanges on the shell but it states that the sabot was a leather sleeve. Now for the definition of a flange the site's glossary says:
FLANGE: A projecting rim or ridge on the body of a projectile. The flange would guide the projectile through the grooves of the bore and cause it to rotate.
Make sense, especially when you look at the shell links above. After all the flanges look slanted so they could certainly impart a corckscrew spin coming out of the rifled barrle. But then you have another Blakely shell with straight flanges (http://www.civilwarartillery.com/hap/page64.htm), looking at this one I have to wonder how the flanges are meant to guide through the grooves of a rifled barrel and cause rotation. This looks more like the grooves in the barrel should run straight and just be a grooved smoothbore rather than a smoothbore converted into a rifled barrel.
And then there's the definition of sabot on the site.
SABOT: The sabot served as the driving band for the projectile, and was made of wood, brass, copper, lead, papier-mâché, leather, rope, or wrought iron. The sabot for a rifled projectile was attached directly onto the projectile. When the weapon was fired, the gases from the propellant charge caused the sabot to expand into the rifling grooves. This, in turn, caused a rotation motion of the projectile which extended its range and improved stability. In the case of a smoothbore projectile a wooden sabot, made of poplar, basswood, linden, or other close grained wood, was used to hold the projectile with its fuze forward and in the center of the bore. Solid shot had the sabot attached with two crossed tin straps. If the wooden sabot was tied to a cartridge bag, the entire round was then referred to as fixed ammunition.
Ok, so the third and fourth sentences there basically say the sabot does the same thing as flanges. So why would the Pattison need both a sabot and flanges? Also, did the sabot fall away from the projectile then like it does today?
Then you look at various James shells. On the canister and grape shot shell section of the field shells I found a James base (http://www.civilwarartillery.com/projectiles/canister/IIIA27.htm) which states that the holes were used to help attach the sabot to the ribs of the base. I'm guessing the ribs being those sections of metal in between the large holes. If so, then whats the purpose of some James shells having slanted ribs (http://www.civilwarartillery.com/projectiles/rifled/IIIA75.htm, http://www.civilwarartillery.com/projectiles/rifled/IIIA73.htm) while others appear to have had straight ribs?