Thanks. I've no doubt they could and did serve as military men, but this is little different than Aramaeans being used as such by the Neo-Assyrians. The Sumerian logogram is only translated into Akkadian as saggasu because of a pun on words in my opinion. You don't make real brigands and murderers into field battalions, charioteers, and troops. The Hapiru were obviously an ethnic group with a common language and possessing all kinds of useful talents but they were also an underclass with a reputation of causing trouble.
Hi Tory Page 25. In the Old Hittite treaty with the Ḫapiru (CTH 17) they were military men, with their name being written in Sumerian logograms as ERÍN.MEŠ SA.GAZ, and who were expected to... more