135mm X 61mm "inert" projectile

This came out of my archive of strange and assorted stuff recently. 135mm tall and 61mm diameter at its widest, smaller threaded end is 40mm diameter. No markings anywhere, except the “inert” label.

What the hell is it?

More photos here.

City Dweller

That’s not a projectile but, instead, it’s an inert artillery fuze. A Mechanical Time & Superquick (MTSQ) fuze, most likely an M577 type. Commonly used on 105mm to 155mm guns and howitzers (and others).