Modern Warfare 3 Zombies - Easiest way to get raygun schematic - Read description
Follow this route and use decoy grenades. If you don't get what you want go start the tier 3 escort contract and pull up tac-map and cancel the mission, then run back to the deliver cargo contract. sometimes it takes a minute for it to respawn so just do some rooftop parkour until it does and repeat. I'm pretty sure you have a better chance of getting more rare rewards later in the game. Good luck and most importantly have fun with it... I definitely am!