It was made at the Utah ordnance plant
U or UT Utah Ordnance Plant (March 1942 to December 1943) - Salt Lake City, Utah; a division of Remington Arms.
Thanks John. I thought it might be UMC "U". I guess i assumed wrong? I was also wondering when LC started making ammo? The LC stuff looks just like this ammo, but is stamped "43". Also, powder appeared to be IMR 4064. Do you know what they used in this ammo way back then?