ya i made my own server to test out all guns and these are the ones that are changed:
mp5, ump, p90, defender, ak, krieg, para, tmp, clarion, m4, bullpup
mostly they are changed from the full auto sound. when you hold down the trigger you'll notice a big difference in the sound. now it just sounds like an echo effect...shouldn't take much to get used to the new sounds if you even use the defaults.