The guns in most call of duty series are getting nerfed and i don't know why can somebody ask me how the Type 95, Famas and so on were nerfed?

Type 95: A burst Fire assualt Rifle, Well-balanced but has terrible hip fire

Famas (Black ops): Full automatic, moderate damage but high recoil

AA-12 (MW3): (Was it Nerfed?)

Barreta .50 cal: (Was it nerfed?)

XM25: (Was it nerfed)

Where any sniper rifles nerfed?