Ah, I didn't check out those two . I'll get back to you!
Firing rate is set in the gun .xdp under 'Rate=', if I am not mistaken.
Apparently it is not as strict as I thought - your two trouble-giving .wavs work/loop fine, even the one that is 7s long. The solution seems to be the wav. format when exporting from Audacity.I thought your idea is based on a fixed time according to your .50cal sound file so how would 7s sound work.
The call for "SoundName=" does not refer to a .wav file directly. You'll find the "c50" entry in the 'sounds.xml' file, where it refers to the "50gun_01.wav" you have in your install... How did you replace the original .50cal sound? I made a copy of the original .50cal sound file for safekeeping, renamed one of the files I altered for you to "50gun_01.wav" and dropped it in the folder, overwriting the one that was there. That worked on my rig.So while dealing with the, so far, unsolvable problems here, I was looking to replace the P47 .50 cal gun sound with one of mine to see if I could replicate Joost's findings. The P47 calls for 50calBrowningM2_gun and that calls for SoundName="c50". No such sound exists anywhere! There are 50gun.wav and 50gun_01.wav and that's it! In nay case, when I replace the 50gun_01.wav original sound with one of mine, in the pit, silence, while outside the original .50 cal sound.