I just bought this thing. It is made of metal. It is about 10" long. Base threads into top. Base Has a threaded hole in the bottom about 3/4 of an inch. Marked B-S on the fin. I don't know if its military. Just thought somebody here would know. Maybe its for training? Thanks for your help.

Here is a link to the pictures

http://www.etsy.com/transaction/68950839

I have never seen the likes of it.

It looks like a toy/trench art, made from a dummy 20mm Oerlikon cartridge that has been threaded into a set of old 60mm mortar fins, although being 10 1/4" long throws me a bit. Whatever, it doesn't look to me like a viable round for any military weapon.

I'd say the silver section is almost certainly a dummy cartridge that was never originally attached to the fin assembly as seen here.

That would be my guess as well although I will go with 81mm Mortar fins as I think the 81mm had 3 holes and the 60mm 2 holes.

Looking at it further I would suggest the fins are from either an 81mm M43A1 shell or an 81mm M56 round.

Really strange. I've never seen that. What bothers me is the black base

It looks like a 5 inch shell with a display stand. It is not attached to the stand and it could never be fired with that bit in the bottom

It looks to be some kind of home made mock up

definitely not a piece of actual military munitions, but it could still be an interesting replica of a pieve of older tech