Why new sounds for machine guns?

[pedrooo14]

Te new sounds are awesome, it feels much more inmersive. The only one I dont like is the Simonov, it sounds weird and unreallistic.

[Acecombatzer0]

The current M4/M16 sounds are OK, they are distinguishable from the other weapons in the game.

When I starting messing around with V1.0's release weapons, and I started to use the FAMAS, on semi-auto for some reason it sounds exactly like the M16A4. Note only on semi-auto, the rate of fire on both weapons are very different.

https://www.youtube.com/watch?v=eBmlvqE24M4

For the FAMAS, shooting starts at 0:30

https://www.youtube.com/watch?v=FxXJSz7Pht8

For the M16A4, shooting starts at 0:43. This is footage from Marine Corps recruit training at Parris Island

EDIT/NOTE: If you look up other M16 videos around Youtube, they sound different, usually due (I think) to different cameras, and well as the environment amplifying the sounds differently. The M16 video I linked takes place in a very open field, and it sounds very similar to the FAMAS being shot outdoors in PR.