Firing mechanic seems to be in GCN_Weapon_Rifle_Fire => which triggers B_Weapon => Fire
In the animInstance ABP_Mannequin_Base you have two parameters
Aiming Data (“category”)
AimPitch (float)
AimYaw (float)
it’s used in functions “Update Aiming Data” & “Set Root Yaw Offset”
As for the control mechanic (inc. aiming) there are a couple of layers of abstraction through data assets and abilities.