Old Pro, you get an automatic 5 year sentence for possessing a gun in Mexico. NEVER carry one across the border, many people that have accidentally driven to an entry port that have been searched and found with weapons get an automatic 5 year sentence - neither your attorney nor the U.S. State department can get you out, it is a nightmare beyond your wildest dreams. You certainly have the right concept, but everyone should be aware of the mexican laws, you can lose your life there easily either in prison or from being unable to defend yourself.
There was an article in Surfer magazine a couple of months ago - some California surfer dudes were robbed, shot, and left for dead by corrupt Federales south of San Diego. I myself am never going to Mexico again until they clean up the corrution there.
I actually did that once. I was in the Army and moving from Monterey, CA to Louisiana.
Anyhow, my car was loaded down with household crap to include a .22 rifle buried under it all in the backseat.
Not paying attention, traffic, etc., somehow ended up getting off I-10 in El Paso and boom, went across the border into Mexico.
Pretty much took the first u-turn I could find and headed back where our own Customs/BP folks stopped me and asked how long I'd been in Mexico and had any plants with me. (LOL!)Said I'd been there about 5 mins and no plants.
And that was it. Scared ********.