Gun running makes a ton of sense re selling in the hotel and bringing up the guns. And laundering profits through gambling. But why were they all different weapons he purchased at retail? That makes no sense. He didn’t have two of anything. He bought them from retail venues.
He would be very small time to be selling guns out of a hotel room. And he certainly wouldn’t be selling guns that could be traced back to him. Gun runners sell contraband military weapons in quantity, not a few pieces of altered civilian equipment like he owned. He was a collector and a murderous sociopath. And maybe a good argument for possession...