The sounds in DeCENT are just Insurgency 2014 sounds mixed with others to get more variety out of them. I do want to eventually replace them. I need to get back with the sound guy I was talking to since we had a plan to incorporate both 1st person and 3rd person sounds (basically give the NPC guns the 3rd person sounds).
As long as it actually feels like I'm firing a weapon, then good. Suppressors also really need some love.