Here are three experimental US Navy projectiles with different styles of plastic rotating bands. All are 3-inch size projectiles. The first two are Mk 23 Mod 0 AA projectile variations. The one on the left has a 1 inch wide band and the middle one a 1 1/4 inch wide band. The right projectile is unmarked and is 10 3/8 inches long. It has a multiple rotating band, the upper one having a raised flange at the base. There is a groove in the projectile body above the top band making me wonder if there were other experiments where four bands were used.