It’s not about tracking guns, and it’s not about gun control.
They were arming somebody up. They intend for those weapons to be used in this country.
There's no evidence of that, but there's plenty of evidence of the gun control angle. Starting with both Obama and Hillary holding joint press conferences with their Mexican counterparts to publicize fake "traced guns" statistic and call for new gun control, and up to and including the Obama ATF order on sales of multiple assault weapons in border states.