C130- took off from Ft Chaffee, Ark. Exited the aircraft, saw the inverted L in pots, did a 360 to check for other jumpers, when I came around no more inverted L. The sky was pitch black so I started counting. At what I thought was the appropriate time, I leaned forward to release my ruck. At that time, I hit the ground face first. The next day I came out to collect my gear and saw the poison oak. 6 guys on my stick had broken ankles/legs.