All Movies have Silly Gun Sounds...
watching The American w/ George Clooney. he's making a custom rifle for a killer chick and she puts it together with classically over done mechanical sounds.
Inserting the clip sounds like a car crash, pulling back the bolt sounds like a train wreck, screwing on the silencer sounds like a Helicopter...etc..
The exaggerated "sounds of a gun" are comical yet 'normal" it's what's expected by audiences...all that sound is manufactured and digitally placed in post production.
Even on low budget TV shows. Gun make Gigantic Noises.
The good news is that the mere sight of a gun will scare some people into submission and you won't need to fire it.
I have a light / laser and it makes my Glock 30 look scarey...a sound effect generator w/ scarey noises could be handy. Something that could emit a loud "Cha-Chunk" at 20 feet.