Hey Mitsu!
Wanted to gratulate you on your awesome soundpack, I am using it!
I have a humble suggestion though, to make it sound even better:
a year ago I modified your soundpack in a very simple manner, I made the different sounds for the machineguns and cannons slightly different in length. I just chopped off 5%, 3% and so on on the various files for the same weapon. That way you achieve a more realistic sound when firing multiple guns of the same kind. In real world, they dont shoot 100% at the same speed also.
Try it!
My best regards!
Matt