In the attached files you will find a pbo that replaces sounds for normal MX rifle AND the MXSW light machine gun.
Normal MX uses SoundSet "MX_Shot_SoundSet" which has only one SoundShader: "DS_FPSound".
MXSW uses SoundSet MX_Shot_SoundSetDirty which has two SoundShaders: "DS_FPSound" and "pinkNoise". "DS_FPSound" is shared SoundShader of both SoundSets.
Note also that PinkNoise SoundShader has volume = 0.
SoundSets MX_Tail_SoundSet can be ignored because for testing purposes the volumeFactor has been set to 0. {F27996}