The new Gunsmith is bringing additional innovations to the overall weapons system. These include more shared attachments and the removal of certain penalties when equipping small Optics.
Attachment Unlocks: For new Modern Warfare III weapons, attachments such as Grips, Barrels, Magazines, and Stocks will no longer require players to use a specific weapon after they’ve already been unlocked for another one. For example, the Assault Stock attachment is available for both the AMR9 SMG (at Level 8) and the Riveter Shotgun (at Level 12). If your AMR9 is already progressed to Level 8 or higher, the Stock will be available on the Riveter immediately, and vice versa.
1x Optic Attachments: As opposed to their counterparts in Call of Duty: Modern Warfare II, new 1x zoom Optic attachments will no longer penalize your Operator’s Aim Down Sights speed, allowing faster target acquisition when using these sights.