CHARLESTON, SCRetired Cpl. Kent Packard, 58, rarely puts his Marine Corps expertise to use, except during the yearly Christmas gift exchange, family sources reported Monday. "Every year, exactly two hours after cutting the ham, Dad makes us line up by the tree, then he distributes the presents to us in increasing order of age," his 17-year-old son Jerome said. "When he unwraps his own gifts, he lines up the pieces of cardboard and plastic packaging in a neat row, like he's field-stripping a rifle." Although family members say they admire Packard's acumen, they've warned him against waking the house with a Christmas-morning bugle rendition of "Jingle Bells."