This one is weird since I looked at the forum and noticed that not a single one mentions about some of the guns having no sounds at all. Some of the guns have gunshot sound while others don't, some guns ONLY have reload sounds and some guns I could only hear the echo of a shot but not the crack of gunfire itself.

I've tried a couple of things. I've deleted the addons and reinstalled them all over again, I've deleted Garry's Mod and reinstalled it again and I even did both and still nothing changed. I'll keep trying other things.