Haven’t found any reference to this projectile. As stated, 37MM.
112.7MM OAL. Solid with burnt out tracer cavity in base. 1lb 14.5oz.
Heavy little bugger. Very hard steel. Apparently designed to create spalling vs penetration, leading to a WAG of anti-tank munition. Faint letters and numbers evident on driving band. Not enough to help.
OK. A 0 and an M.
Probably expended all its energy without hitting anything of significance as only minor scuffing is evident.
Anybody got more info?