heres a link to the vtf, just crack it open and have a looksee at the sounds

https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=3254140946

Send me the file (both the regular gunfire and incendiary ones, pls), and I will add it to the mod, then. I am afraid that if I try to do something myself again with that file, I will end up crying in a corner

You gotta speed up the audio by x2 to get it to sound right after you re-render it into a new 44100hz track, because since you're doubling the hz you gotta double the pitch of the actual sound file to make up for what the L4D2 engine was trying to do. Speeding it up is gonna make you need to add a whole lot more than 1ms at the end of the track to get it to the original duration, though on my version I didn't have to add any extra 1ms of time my audio clip uses the exact same number of samples as the original clip. I don't have any mono issues though I hear it just fine in both my ears. I could share my VPK if you'd like.

Interestingly, this cursed shooting sound works fine with this sound replacement for the MP5

Managed to recreate the issue.
The original files taken from the MAC-10 version are at 22050 Hz, but they do not have any issues with or without the MP5 mods.
Changing the sample rate leads to the audio being played as mono (even through the file is actually stereo) and additionally causes screeching sounds immediately instead of at the end of the audio track.
Adding 1ms at the end of the track solves the screeching issue, but makes the sound to be played as mono despite still technically being stereo.
No matter what I do, it just does not work properly. I have done sound replacement so many times without any issues for other mods (the process is shown in this guide ), but this one is just cursed.
I will probably just remove the gunfire sounds, so you can use this mod with any sound you like

I found the issue, I think it has to do with the frequency of the audio files. This might be an artifact from the OG original version of this mod that was for the MP5, because at some point CS:S weapons needed audio files with a frequency of 22050hz instead of everything else being able to use 44100hz audio files. This is also why the audio sounded lower pitched in the first version I think, because even though today the audio sounds right in this mod (sans screeching), when I decompiled it and listened to the raw audio it sounded like it did before being twice as low of a pitch. The screeching must be coming from the game taking the low pitched 22050hz file, and playing it at 44100hz, making it the correct pitch but have horrible screeching when the sound stops playing, at least for me.

In my fix, I re-rendered the audio file to be 44100hz, sped up the sound by x2 to make it sound right, and then filled the empty space with empty audio to match the original length of the file, with a little bit of fade-out between segments to avoid any clipping when the actual audio stops. I think if you implement this in your mod it'll play nicer with other mods. If you want to try recreating the bug with the specific mods I was using, I was testing it with this mod and this mod. You may also want to consider doing this for the MAC-10 version because it might be creating conflicts for other mods. Why only the mods I've tested and not any of yours IDK, it's worth looking into and some rigorous testing and debugging though to make sure everything works right.

I could not replicate the issue, and also I do not understand how a different mod with different sound files put in a different folder can affect another mod. Tested this UMP with two MP5 mods — no audio glitches. The length of each audio file (not just the shooting sounds) is the same as the original audio for the Uzi

IIRC screeching problems are caused by sound duration issue, been a while since I've done any modding myself but might be work looking into

Shooting sounds really good now, but if you have any mods for the MP5 it causes an AWFUL screeching sound after you stop shooting. It's not specific to one mod either, any MP5 mods cause the UMP to screech. Solve that bug and it'll be perfect!

Какой ужас

换弹有怪声

Updated

Will try to fix that. I used the same sound as in the MAC-10 version, though, but adjusted it for the Uzi to avoid getting audio glitches

This is nice, but it uses the wrong firing sounds, or at least if its intended it doesn't sound the same as it does in the video. Only thing wrong with it :)

nice