Hi Roslyn,
Your father as well as mine. Was in a WWII service unit. This was the only way the military want our father's to service. In service to white units, our father couldn't be trusted with guns. We have only fought in every war this country have been in, can't be trusted.
The 590th was an Ordnance Unit. These units took supplies (ammo in this case) from the beaches to the front.
The 590th Ordnance Ammunition Co. - Manila.
My father was in the 595th - Leyte.
I hope this can help.

Happy Hunting

gog