That's straight-up cheating. The rate of fire is all wrong, with no delay between bursts (which a pulse rifle with auto-fire would have). Not sure how it's done, but I guess he's using a PC as a proxy (passig his connection through it), with something editing network traffic to/from his console running on it. To those who were wondering, a modded controller can't do that unless a) there is no software fire rate limit (which there is) or b) there's a bug like the Hammer of Sol spam glitch (unlikely).