It's a crappy video that demonstrates almost nothing.
He claims he's never found a drum magazine that doesn't jam. Strangely enough, a lot of other people don't believe that because they do sell a lot of them, some are rather high-end stuff.
He has no evidence at all that the shooter did use belt-fed ammo. We haven't seen anything to indicate this in the hotel room photos. We have no mention from his firearms purchases or ammo purchases that he was using belt-fed ammo. The police have certainly confirmed the use of bump-fire stocks but made no mention of belt-fed adapters on his guns.
