Apparently they were using foreshafts on their arrows
"To attach the points to the arrows, people split or sawed notches into the ends of short, narrow sticks, and then inserted the point, probably with a dab of pitch or other adhesive, and then wrapped the end of the stick to secure it. This piece, called the foreshaft, could then be inserted into the end of a long, straight reed, forming a lightweight compound arrow. If the arrow point broke when it either hit the target or missed and hit the ground, the archer could easily re-arm the arrow by pulling out the foreshaft and inserting a new one with another point already attached."