Here’s a comparison video comparing guns which are both in the giants, but are infused with different sounds.
I thought that all of Battlefield’s guns sound similar, probably because they were all recorded on a mountainside. Modern Warfare 3’s guns sounded different from each other, probably because they were recorded at different locations.
The comparison shows how much time and effort the teams have put in infusing the weapons with unique sounds.
Which sounds are your favorite?
Source Designing Sound