The weapon sounds sound perfect to me. I've heard much much much worse sounds in games. Call of Duty 1 had some really terrible sounding ones that severely lacked treble which generally makes sounds feel 'sharper'.
Contrary to what people may think, in real life two weapons will never sound exactly the same... They may sound very similar but there are so many factors that affect how a weapon will sound... More than you could even think of. First of all is what type of amunition and caliber then there's a multitude of other things like local air pressure, density of the wood used in the stock, condition of the metal - including fractures, density, minor machining defects - also how it's welded, barrel friction, blowback action friction, gas pressure, reciever friction, density... Pretty much every aspect of how a gun is constructed and operates all individually have a small effect on how the gun sounds... That's not even factoring in how the immediate environment can effect the reverberation and distortion of the sound waves.