without access to a firearm.
In practice, possession of firearms above .22 caliber is severely restricted. As with much of the rest of Mexican law enforcement, corruption is a major element of the gun licensing system.
Because government permits are difficult to obtain, there is a thriving market in smuggled handguns from the United States. One effort to control smuggling was Operation Forward Trace, conducted in the 1990s by the U.S. Bureau of Alcohol, Tobacco and Firearms. BATF agents examined federal gun registration documents (Form 4473) held on file at gun stores in southwestern states, and recorded the names and addresses of buyers - especially those with Hispanic names - who had purchased self-loading rifles or inexpensive handguns. BATF then contacted the purchasers, and demanded to know where the guns were.
In July 2001, U.S. Attorney General John Ashcroft and Mexican Attorney General Rafael Macedo de la Concha announced a cooperative law enforcement program, aimed partly at weapons smuggling. Mexican police would provide computerized information about seized firearms to the US Bureau of Alcohol, Tobacco and Firearms (BATF) so that BATF can trace the guns. for criminal investigation. Ashcroft also assigned US prosecutors in districts bordering Mexico to serve as contacts on gun smuggling cases.
Even government agencies, frustrated with the Defense Ministry, sometimes smuggle in their own weapons from the U.S.
In August 1985, the army -- using the pretext of a routine inspection -- confiscated the weapons of the Juarez police. Many observers believed the confiscation took place because the city government was controlled by PAN, the leading opposition party. Guns confiscated by the police or the military often end up on the black market.
http://www.davekopel.com/espanol/Mexican-Gun-Laws.htm