Obviously the brake lock screw has been cross-threaded. My guys learned to not do that. The hard way if necessary.
Suspect it's probably a Stug Barrel. Early brake for an L/48 or similar. There are (probably 'were' is more accurate) assorted similar efforts in Normandy. Annoyingly, I can't find the pics of a couple of upright gate posts with Stug barrels etc. ( @Owen - help!), but this'll do (Via the Weald Foundation), which I think may even be the full sockelafette mount: And if you find yourself with a surplus of Panther wheels... why not? (Said to be Bulgaria)
I can't remember where I got the pic from, but what I do remember about it that it was a German 75mm cannon barrel from a PzIV. Guess it could've been from a Stug too. Not sure where this pic was taken though.
I remember when we sailed in and later out of Le Havre on the SS United States they had Panther hulls as the basis of their movable cranes. Wish I had pictures.
Kind of a relief to hear direct memories of the Panther cranes. Have often deployed that pic and some weirdo cries 'Photoshop!'. Why, I will never know.