This artillery quadrant was probably part of the instruments used for teaching balistics.
There is a quarter circle between the two quadrants with a seven centimetre radius, divided in ninety parts. The plumb-line needed to measure the altitude of the guns is missing.
Its use is described in Niccolò Tartaglia’s 1537 La Nova Scientia which illustrates "how to aim a piece of artillery the furthest it can fire ... for which purpose a square is needed of any metal or hard wood with in between a quadrant with its perpendicular...placing part of the larger leg into the barrel of the gun".