The problem is that there is no such thing as a real sound effect. Cameras aren't ears. You have to overemphasize to even remotely mimic the true effect of gunfire. The sound has to overprovide, because the shoulder bruises and smell of powder isn't there.
And for the record, CoD sounds are usually a dull, muddy thumpa-thumpa. Not a good model at all. Even with vanilla sounds, you average CoD firefight would be absolutely thunderous if re-created in ArmA.