It's more a curio than anything. I see them at yard sales now and again for around 20 bucks.
I may be wrong, but to me, it looks like a German 7.7cm FK 96.
Loaded by Friedrich Niemeyer (FN in circle) from a heavy shell (St - Stark, reinforced) made at Haniel Luege Düsseldorfon (HL - and 27 being the inspector mark), February 1917, Lot 25




























