The 3 inch M2 MII is a much taller shell casing than the M18 - about 150mm longer (6 inches). I have never seen a US projectile with a dual driving band though.
Do shells have brass driving bands,?serious question as I have not seen one before and they look like brass,
Don,
-the projectile has no adapter so it should be not a shrapnel shell
-it is missing a bourrelet which every shell should have
-no stamps on projectile body
-a never seen driving band arrangement
-a WW1 fuze in combination with a 2nd WW brass case
-obviously brass material instead of copper for driving bands
-a very smooth surface without lathe marks (polished after turning process?)
Is it a real shell or just a good but wrong lathe work?
The 3 inch M2 MII is a much taller shell casing than the M18 - about 150mm longer (6 inches). I have never seen a US projectile with a dual driving band though.
Bellifortis,
In regards to your primer question. As artillery became more powerful with greater pressures in the guns, the U.S. went to a two-stage primer. The centermost piece in the primer that can be seen, will actually move forward and back. It has a firing pin shaped protrusion that faces forward on the inside. The steel firing pin in the breech mechanism of the gun travels forward upon firing and hits that center piece in the primer. The floating piece travels forward and hits a percussion primer which ignites the propelling charge. The floating piece is a safety, to prevent any hot gasses from escaping from a possibly pierced primer. If gasses escape the pierced percussion primer, they push the floating piece rearward, sealing that passage and preventing any leakage.