User blog comment:Arbington/My Multiplayer Ideas/@comment-4672495-20120804061816/@comment-1221773-20120804181055

Prior to ME2's release, there was a BioWare blog post explaining that as Shepard discovered weapons during missions, they would be taken to the Normandy and duplicated for squadmates using the ship's fabricators. It's possible that as advanced as the Particle Rifle is, it isn't beyond the capabilities of modern galactic technology to duplicate on a large scale.