Could be fabricated but the Halo assault rifle a Has no sights, no slide. How is it powered? A gun requires alot of moving parts, which the AR doesn't have. The sniper is fairly realistic. But all the guns in Destiny are "acceptable" seeing as how none of them are "Human weapons" they are all futuristic and science fiction. Some of them could be fabricated in reality and work. But my point is.. its a game (a Sci Fi one at that). Why does it matter if the guns are realistic?