There are a number of changes to Black Ops 3 weapons. Many of these were already live in the game through hotfixes, but there are some new additions. Check out the changes to entire classes and to specific weapons below. There is also a major change to the Awareness perk that reduces the usefulness.
General
Fine-tuned Rapid Fire effectiveness across all weapons.
Submachine Guns
General - Reduced sprint out speed
VMP - Fixed issue where Player would occasionally not show on the radar when firing.