Please measure the outside diameter of the barrel at the muzzle.
Machinery"s Handbook #24, meteric conversion table on page 2455 says:
Millimetre times 0.03937008 equals inch
Now plug in the values:
14mm X 0.03937008 = 0.55118"
Therefore, you barrel at the muzzle end will have to be about 0.551" in diameter in order to thread it 14mm X 1 left hand thread.
Thumb Clip Pull Pin.