On August 4, the Risk Analysis Unit (UAR) Custom Algeciras noticed a suspicious container headed out to the US by ocean freight. The Bill Of Lading indicated dismantled weapons. However the UAR decided to seize the container for a full inspection. This is common for ocean freight and customs. I used to work for a Freight Forwarder and we imported containers of shipments from Asia. US Customs often runs random exams/inspections on containers. They can be as simple as a full container x-ray or in this case a full inspection and every item is pulled from the container and matched up with the packing list and invoice.
The UAR pulled this container and found it full of Sig 553s. 737 of them. Along with 72 Swiss made grenade launchers.
Here is a different video of two agents opening the container.