Thread:BehindTheEight/@comment-24727856-20140324050316/@comment-6969786-20140324052929

Im not 100% sure but...

Belt Feeder says "Increases machine gun fire rate". So fire rate i would say is just for the Machine Gun.

Percision Barrel, I don't know if it effects the other weapons but this one should be easy to test.

Optimized Assault Barrel also can increase Fire Rate but it does not specificly say Machine Gun in its discription so... maybe this on effects the other.

I guess you could use one with and one without and see if you can see a difference in rate.