That's generally how audio editing works, as I understand it. If you limit yourself to only actual gunshot sounds for gunshots you don't have much to fine tune. Lots of people use various random things like laser and electrical zapping effects layered in there to get a bit more oomph. Considering there are many layers, it's not like you'll actually hear a woman screaming, animal noises, or voices (unless you're crazy) when you fire a gun...it will still sound like a gunshot.
I remember reading an article about Burnout Revenge in a PlayStation magazine of sorts way way back. The interview revealed that the audio guys resorted to sometimes dropping dry ice on sheet metal and even slashing at each other with ninja swords to get sounds for crashes.