Fast and Furious is a favorite hobbyhorse of the right that should be laid to rest. 

"About 2.2% of U.S. domestic arms sales between 2010 and 2012 were attributable to firearms trafficked across the U.S.-Mexico border. ... The mid-range estimate suggests that the combined seizures of roughly 37,000 firearms by Mexican and U.S. authorities represent roughly 18.2% of the weapons bought for trafficking in recent years... [There are] three gun dealers for every mile of the U.S.-Mexico border."

https://journalistsresource.org/studies/government/criminal-justice/firearms-trafficking-u-s-mexico-border

Fast and Furious was an attempt to track some of this illegal trade, and the guns lost represent a drop in the bucket of cross-border smuggling. Right-wingers are angry, not because guns made it across the border, but because the lucrative smuggling trade was being investigated in the first place.