5,000 .38 Super rounds
This is a round very rarely seen these days, outside of competition shooting. USPSA/IPSC "race guns" are usually chambered for .38 Super, due to the fact that they can be classed as "major caliber" while having a much lower recoil than other major caliber rounds. And much safer than trying to load 9mm to major caliber power factors.
10mm would also be unusual for criminal use. I wonder if they actually busted a competition shooter - That amount of ammo for a competition shooter would last less than a month.
.38 Super has long been popular in Mexico, because the .45 was outlawed for civilian ownership as a “military” caliber.
10mm has a prestige factor for the bangers. In 2006 a Sheriff’s Deputy in my neck of the woods was killed by a thug with a Glock 10mm during a traffic stop. It’s seen as a macho round.
These rounds make sense if they were going to smuggle them into Mexico.