parts list from mlcad.. i was really lazy
No. Color Part no. Part name
11 Light-Gray k108.dat K'nex connector 1 gray
1 Tan-Solid k119.dat K'nex connector 1 tan
1 White k207.dat K'nex connector 2 gray
3 Orange-Solid k225.dat K'nex connector 2 orange
1 Red k304.dat K'nex connector 3 red
6 Green k402.dat K'nex connector 4 green
1 Light-Gray k0002.dat K'nex rod 0 green
1 Yellow k1114.dat K'nex rod 11 yellow
1 Red k1804.dat K'nex rod 18 red
1 White k0315.dat K'nex rod 3 white
3 Blue k0601.dat K'nex rod 6 blue
numbers in bold are the number of that specific part you will need....i think there is 30 parts.
Step 1: Ram Rod
Step 2: Barrel.... and Trigger
Step 3: Handel.... Added on to Barrel and Trigger.
Step 4: Put It Together!
and its your choice of how u put the elastic band in... there is many ways. good luck and happy instructabling.