來復線

rifling (spiral lines on inside of gun barrel imparting spin to the bullet)

to come / to arrive / to come round / ever since / next

to go and return / to return / to resume / to return to a normal or original state / to repeat / again / to recover / to restore / to turn over / to reply / to answer / to reply to a letter / to retaliate / to carry out

thread / string / wire / line / CL:條|条[tiao2],股[gu3],根[gen1] / (after a number) tier (unofficial ranking of a Chinese city)