Greetings, Devil Dog! Welcome to the Call of Duty Forums. It looks like you're looking forward to Call of Duty: Modern Warfare 4, but haven't created an account yet. Why not take a minute to 
Activision & Infinity Ward released a new trailer with an overview of Infinite Warfare's new Weapon Crafting system. With Weapon Crafting, you can modify a base weapon to develop into upgraded, crafted weapons.
View: https://www.youtube.com/watch?v=nF8QBsmy8hs
