F. Bergman was a "Musician" in Co. D, Cook's Regiment heavy Artillery. On a "Regimental Return" record for the month of April, 1864, in the section "Absent enlisted men accounted for:", is the following handwritten entry: "On det. service to Sabine Co sp. order no 84 ??? ?? Cooks Rgt. to return May 17/64" The question marks are mine; I can't make out two abbreviations, though they might be "ltd. Gr." Can someone help me understand what this might mean?