Which document might be incorrectly assumed to inventory unexpended ammo?

The DA Form 5131-R is a designator for a document that primarily deals with the requisition of ammunition, not the inventory of unexpended ammunition. This form serves specific logistical functions related to the management and warehouse transactions of ammunition, rather than providing an accurate accounting of ammunition that has not been used.

In contrast, other forms like the DA Form 5515, DA Form 581, and DA Form 3151 each have distinct purposes related to ammunition management and inventory. For example, the DA Form 5515 is a document used for the inventory of ammunition and explosive items, while the DA Form 581 is used for the request for ammunition and components. The DA Form 3151 is the ammunition transaction report, which includes data on the receipt and expenditure of ammunition, ensuring a comprehensive tracking system.

Understanding the primary functions of these documents helps clarify why the DA Form 5131-R does not serve the function of indicating unexpended ammunition, making it the least likely candidate for inventory purposes in comparison to the other forms.