You can find that stuff (and their sources) out on Halopedia... or from weapon focused Bungie Weekly Updates from the H3 era, weapon articles on Waypoint, the Halo Essential Visual Guide series
Halopedia Link: MA5
Still, that involves a lot of looking around when the guy just has all the weapon info right there.
Oh who am I kidding, I've spent hours reading the Halopedia and Halo wikia about things like the flood and various covenant stuff.