I carried concealed -- as did and still do almost all of my close friends down there -- for the last 10 years of my 26 year "first long stay" in Mexico, starting to carry on September 16 or 17 of 2008 (just after one drug gang in Michoacan threw hand grenades into a crowd of women and children at an Independence Day gathering in Morelia) until I left to come back to Canada for a 6 year "gonna turn 65" work-a-thon on July 9, 2016. Like all my friends practicing what they preach, we were not "carrying with permits to carry" but were carrying because it had become dangerous all around us. Being spotted actually carrying by Security Forces could get you shot up just as quickly as not having a gun could get you shot up by the bad guys should you be in the wrong place at the wrong time.
For most of that time, I used my Model 49 no dash in a Bianchi Pocket holster. I still use the same holster when we go down for visits but usually carry my wife's Model 60 no dash because my wife's is stored in Salamanca where we usually stay and mine is over in San Miguel in our old reloading room -- which might as well be on the backside of the moon when one is walking around Salamanca these days. My chosen load is a 160 grain Lee LSWC TL bullet and 4.5 grains of Bullseye, with the bullet crimped into the top tumble-lube groove. Recoil is harsh and hurts my girlie hand but power is the name of the game because if you need the gun, you need it to do the job intended which is putting armed bad buys down right now if possible. At the same time, it has to be hidden and stay hidden all throughout your normal day. As has been so correctly mentioned by Diamondback Six, you must adjust your lifestyle and wardrobe to help ensure the gun stays hidden. Remember: Security Forces will kill you in a heartbeat if they suspect you are armed and feel threatened by that and nobody is sueing anybody, so you must be prudent. Also, potential attackers will kill you out-of-hand if they suspect you are armed and your only advantage in any confrontation is that they in fact believe you to be unarmed and thus make the mistake of getting close to you -- at which point a powerful 5-shot snubby is not at such a disadvantage.
In situations where I was in locations of a more "rural" setting I would often carry something larger and often drove around the back-country with just my S&W 3904 in a Jackass Original because I would be able to see anyone I came upon from far enough away to decide on whether to stow the gun or at least cover it up with something. Downtown Bananaland is not a place for blond haired foreigners to be spotted carrying.
My 3904 and the Jackass Original shoulder rig.
Even if the President of Mexico gave me a permit to carry, or the General of the 16/A Military Base in Sarabia gave me a letter authorizing me to carry (which is almost about as good and actually happened once), I would stay with my snubby. Not because it is the best gun or my favorite gun, but because it is concealable in constant warm weather and just powerful enough, I hope, to do the job. Remember: the Security Forces will quite possibly kill you if they feel threated coming upon an armed civilian in the grocery store, and the bad guys will do the same. Also, unlike the Okanagan for much of the year, Mexico really is a warm-weather climate. You won't be over-dressed most days.
And your very life depends on it. Not just having it on you, but never being spotted or suspected of having it. "Concealed Carry" as a concept where the Nation State lets you take a course and then gives you a permit to walk around armed is a rare and precious thing on this planet. Often, only the rich, powerful or connected "elites" can even apply. In most countries, especially the more dangerous ones, one is on one's own and must make the decision between being an unarmed victim or being an illegally armed player. From what I saw in Mexico and continue to see to this day, most people prefer to choose to be an unarmed victim over being an illegally armed player. It's a frightening reality, and speaking from experience, it takes a while to wrap your mind around the concept when it's actually happening to you and all around you.
But once you're there, of course, you've crossed a bridge you'll never have to recross and in many cases -- not always but many -- you become able to recognize others who have crossed that same bridge as well. Knowing this, and recognizing this, always makes me feel slightly nervous when I see that Army Sergeant just outside of the Mega Commercial with one hand on the GPMG of his squad's truck watching me as I walk with my wife's Model 60 in my pocket towards the entrance door his Lieutenant decided to park in front of. Does he know? Can he tell? Can he see that little bulge?
It's sure not a game.
My Model 49 and the Bianchi Pocket holster.
It leaves a bit of a bump even on the good days....
Untuck the shirt. It's too warm outside most days to do much else. A/C isn't used much in Central Mexico away from the tourist haunts. Don't get caught.