Why would you give someone your kilt?
The expression hearks to the 27 feet of belted ammunition, as has been pointed out by posters and their echoes. That, however, doesn't stop the revisionist historians from thinking up non-martial origins for phrases we use. Remember the genius recently who tried to pass off "molon labe" as some pansy french quote? Heaven forbid it should be violent in origin and stand for a principle. Good rule of thumb: If any historical item is attributed to a politically correct origin, your information is probably wrong. We of the late 20th century are the only ones to be concerned with such bull excrement.