This mod from RuhigSein will replace all weapon firing sounds with those of a recording of the actual gun.
Readme File:
Realism Gunfire
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by RuhigSein
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Installation Instructions:
*Extract(or Copy and Paste) zzz_Pleiades_Realism_Gunfire.iwd to your Activision/Call of Duty 2/main folder
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Uninstallation Instructions:
*Delete the zzz_Pleiades_Realism_Gunfire.iwd file from your Activision/Call of Duty 2/Main folder
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They're the exact real sounds for these guns.
Guns don't sound very different, and some sound exactly the same.
The sounds are a tad bit altered, to fit better for the game.
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Updated. All guns and cannons have more bass.
Removed explosions and reloading sounds. Only guns are changed.
Email me for hate mail. >:)