[GH85Carrera]

New Zealand Officers of the British Expeditionary Force with a captured German anti-tank rifle in Second Battle of Bapaume, France, during World War I — the German Muaser 1918 Tankgewehr, a 13 mm anti-tank rifle. Weighing over 41 pounds, the T-Gewher was the world's first anti-tank rifle; the Germans fielded some 15,800 before the war ended. The single shot, bolt action rifle had an enormous recoil and no recoil reduction system, not even a padded butt stock; operations was painful for the shooter.
That would be a cool wall hangar trophy for a gun lover.