The hand is the engagement bar that feeds through the slot in the blast shield and ingages the cog on the back of the cylinder to rotate it. The hand spring is less than a 1/2 inch long and rides inside the fork of the trigger. One end fits into a tiny hole inside the fork of the trigger and the other end must be compressed and fitted behind a pin as the hand is slid into its retaining hole. Not easy to do without experience. A tiny cup tip punch is useful to hold the spring compressed as the hand is slid into place. Spring must be oriented correctly. Hopefully the spring is still up inside the trigger fork and hasn't wondered off. Here is a link to your schematic. Look at parts 27,28,30

http://www.brownells.com/.aspx/pid=0...l/J_Frame_60_4