I put 9x19 next to the knurled one for comparison.
Looks like a Swiss dummy.
This is a Swiss solid brass drill/dummy round. I five other variations of this brass drill, three with the knurled band painted tan and two painted black. Some have a “+” headstamp and some , like yours are plain. There are a number of different diameter firing pin holes in the base. During WWII this drill was made of aluminum with a black painted knurled groove. This round has the “+” headstamp. I also have three similar steel drills with black painted knurled bands, one with a “+” headstamp and a the two plain head steel drills have different diameter holes in the head.
I have heard opinions that all are for the military and opinions that only the “+” marked drills are military. I have no idea which is correct.
There are undoubtedly other variations of this Swiss drill with the knurled band.
These scans show the dummies Lew explained above.
First block brass dummies, second block first left Aluminum, next steel