trying to figure out what it might be, any ideas?
I don’t know what you got there but to me, it looks dangerous.
Hard to guess without anything for a size reference, but the general shape is reminiscent of a 2.75in rocket warhead. The warhead joined the rocket motor/rocket body by the use of splines that inserted through slots in the rocket body into that groove at the base of the warhead, locking those two parts together. That general profile could be a practice warhead, with or without spotting charge, or HE or WP. Look for identifying markings, traces of paint, or other ID features. Until you can identify, you should treat as a potential hazard!
Agree it does look like 2.75" folding fin rocket wearhead. The warheads are threaded into the front of the aluminum rocket motor body, and it looks like the motor tube sheared off around where the threads on the warhead end.
Taber is the professional on these sorts of things, and if he says treat it as potentially hazardous, please do so. They made a lot of these with inert loaded warheads using regular warhead bodies, so not knowing what is inside makes it prudent to assume it might be the bad stuff. No one knows if it came from a target range, aircraft crash site or surplus scrap metal pile.
If in doubt, take it to a safe place outside away from your house before calling the local cops, who will call the bomb squad, fire department, TV news crews, etc and have a circus for several hours.
If you are in doubt DO NOT MOVE IT YOURSELF.
Let police/mil EODs handle it.
About ordnance: leave what you don’t know. We all on this Forum can give you even living examples of bad endings.