Some weapons like the Medic shotgun and M14EBR don't use the correct 3rd person sound effects. The medic shotgun uses an entirely different sound, and the M14 uses the deagle's sound. But the point is, it's not the same sound that's in first person. Pretty much all guns sound better in 1st person than they do in 3rd. I'm sure there's a few other weapons that I missed, but these ones are the ones I keep hearing.