As posted on another forum. Any help or ideas would be appreciated. Thanks, Bruce.
As can be seen by the pictures, this one is a puzzler. It at first appeared to be a Schenkle round, but the rotating band threw that out once the rust and mud were knocked off. Now that I’ve bead blasted it, some of the functioning comes to light. There appears to be a forcing band behind the rotating band since it is a separate part and has a slight gap in it that would act to trap gas and expand it forcing the rotating band in to the rifling. The interior is pre-fragmented in a diamond pattern with most of them being about 5/8” wide and 1” long. I’m pretty sure it is of U.S. origin and 1900-1917 era. Other than that, I have not a clue. The measurements are following.
Dia @ Rotating Band: 3.150” Rotating Band Width: .570”
Dia @ Major Width: 3.007”
Dia @ Mouth: 2.200”
Over All Length: 10.750”
Body before Step: 5.300”
Dia @ Step: 2.570”
Body after Step before End: 4.700” Flange Width after Step Length: .750”
End Piece Length: .750”
Dia of End Piece: .810”
Thanks for any help. Cheers, Bruce.