I'm currently making a Halo: Combat Evolved game on Roblox, which will sort of be an "advanced firefight" mode, and I'm looking for a reliable site where I can find sounds for everything. I downloaded Sillygoose's sound pack, but there are a few sounds that weren't included such as single shots from fully-automatic weapons, as well as picking up certain weapons.
"If you don't say goodbye, you're never really gone."
This is going to sound like a wild goose chase, but there is a Department of the Army that deals solely with aural (audio) combat. They are the guys who deploy that huge sound thing used in the Hulk (yes, it's real). If you could find their home base, I would bet you they would have some outrageous sound recordings, or know where you could find them, as they tested many different types of sound while designing and testing this thing.