Lego ABR Automatic Blowback Rifle (+ instruction)

1080p only! :) Automatic Blowback Rifle. Thank you for your help, guys! Instruction (in Lego Digital Designer) LDD file: #!X1hHGIyD!G9cR_W1LXyQAG4VUr8CyLyYhHSnmgKHANRa1Pae20XY or Photo of the mechainsm (help in placing rubber bands in the rifle) Blue pieces in LDD are on incorrect luck in building! :)