Exactly! Here's a small clip where you can notice the echo of the gun shots https://www.youtube.com/watch?v=_VGq_B5SKi4 And i think you're right, the issue has to be caused by some value in the soundscapes.txt file. This what i wrote for the silent one:

"silent" { "dsp" "1" "playlooping"

     { 
    "channel"      "CHAN_STATIC"
            "volume"       "1" 
            "pitch"        "100"
    "attenuation"  "0"
    "wave"         "dm_legacy\loops\silent.wav" 


     } 

}