SNAPSS lost some functionality in 1.7a2. Specifically, the code no longer recognises missiles, and instead defaults to the basic laser sound. Exact cause is unknown. previously, the game would treat a missile as a weapon of any other type, and play the appropriate (sorta) sound based on damage type and roll. This may indicate a bug, a fixed previous bug the mod was accidentally relying on, or both.

Download of SNAPSS in this forum post: https://forums.kronosaur.com/viewtopic.php?f=24&t=7643#p68921

assumedpseudonym 26 Aug 2016:

 If a weapon doesn’t have a defined sound, SNAPSS plays &snLaserCannon;. (This is supposed to be overwritten to be a silent WAV file, but the previously ticketed caching issue is reinstating the file defined by vanilla instead of by the mod). The real problem here is that the launcher defines the sound, but SNAPSS takes its data from aWeaponUNID in <OnSystemWeaponFire>. In the case of a launcher with multiple ammo types, aWeaponUNID is the missile rather than the launcher. Missiles do not have a sound defined, which causes SNAPSS to play a silent WAV that has been replaced by the original sound effect by the game engine. This is basically two bugs working in concert to cause the problem.
 The best fix for SNAPSS would be having an aAmmoUNID variable to check, and for me to make fixes to SNAPSS once the variable is available. In the meantime, the quick-n’-dirty fix would be to have weapons that don’t specify a sound to play &snMissileLauncher; and rely on the caching bug (or just outright copy the WAV file and have that play), but weapons that are specifically supposed to be silent would suffer unless their code includes a silent WAV.

 See also:
http://ministry.kronosaur.com/record.hexm?id=57968
http://ministry.kronosaur.com/record.hexm?id=56594
http://ministry.kronosaur.com/record.hexm?id=22224
http://ministry.kronosaur.com/record.hexm?id=3022
http://ministry.kronosaur.com/record.hexm?id=805

george moromisato 26 Oct 2016:

Fixed! Thank you!