By the time of the classical engagement at Agincourt Neil the English archers had got all that sussed out and chain mail, if you could afford it, was by now two layers thick.
The archers countered that with the Bodkin point. It was long, square in section and thicker at the shaft end than the shaft.
This meant that the point had a good chance of of passing clean through the mail links, and as the shaft was smaller the shaft's inertia carried on pushing it.
The point was socketed and not a particularly tight fit so pulling the shaft would normally leave the point inside the wound.
This happened to the 'Black Prince', he was saved by a device made especially for the job that had two spoon ends that were open and closed by a thread. It was pushed into the wound then opened to pass either side of the point then wound closed then withdrawn taking the point with it.
Infection was prevented by plugging the initial wound with Honey then sealing the wound after wards with more honey. He survived to the age of 45.