When he formed Calibre 50 with Вguitarist Armando Ramos, who adds the Вshimmer of a 12-string, they adapted to their Вenvironment by forgoing a bass and adding the boisterous marching-band honks of a tuba. Because MexicoвЂ™s Pacific Coast is a bastion of horns and woodwinds, MuГ±oz, the son of an elementary school teacher and aВ homemaker, picked up the accordion out of pragmatism: вЂњThere was nobody else that played it.вЂќ NorteГ±o music gets its name from the northern borderlands of Texas, where accordion-loving German and Czech immigrants settled in the 1800s. Of course, Calibre 50 also refers to the bandвЂ™s music -В penetrating hearts, cultures, borders. вЂњNo armor can stop it -В only God,вЂќ says MuГ±oz, who greeted me before the show at the MGM, where the band had stopped to shower after driving in from Salt Lake City. A 50-caliber bullet is reputed to be the worldвЂ™s most lethal. Even the bandвЂ™s name tries to have it both ways. вЂњThere may be a shitload of very tall buildings, a shitload of casino towers, but without all you -В you, who bust your asses -В the bonfire wouldnвЂ™t be the bonfire, nor would the United States be the United States.вЂќДЇrom the bandвЂ™s start in Mazatlan seven years ago, Calibre 50 has performed a balancing act: sweetness and swagger, the propriety of traditional ranch life with a splash of gunslinger danger. вЂњKeep in mind that youвЂ™re the ones who make it all run,вЂќ MuГ±oz tells a whooping crowd between songs. Before a Вluminous sea of cellphones greeted the band outside the Silver Nugget, the Вmembers of Calibre 50 had strolled through the MGM Grand, in crocodile-skin boots and rabbit-skin Вsombreros, Вunbothered -В as invisible to the raging Вfantasyland of Vegas as the Вimmigrant laborers they came to entertain. Still, to tour the United States as a top regional Mexican act is to straddle Вparallel Вuniverses of adulation and anonymity. The groupвЂ™s latest hit, вЂњSiempre Te Voy a QuererвЂќ (вЂњI Will Always Love YouвЂќ) -В which it Вperformed on ConanвЂ™s recent вЂњConan Without Borders: Made in MexicoвЂќ Вepisode -В is one of its biggest yet, amassing more than 100 million YouTube views since December. On Spotify, the band boasts 2.2 million monthly Вlisteners, and, this year, it is a finalist for three Billboard Latin Music Awards. 1 songs on the Regional Mexican Airplay chart since 2013 (more than any other Вmusical act) and two No. вЂњItвЂ™s universal.вЂќД«y marrying sly, romantic crooning with the countrified oompah of accordion and tuba, Calibre 50 has scored eight No. Вmarketing and promotion for Fonovisa-Disa, the label that represents Calibre 50. вЂњRegional Mexican is not regional Вanymore,вЂќ says Sergio Perez, vp U.S. With millennial acts reshaping the face of regional Mexican, a Вcategory Вencompassing everything from the Вmariachi-laced Вballads of ranchera to the Вfrenetic horns of banda, Calibre 50 is Вleading the charge, a resurgence largely out of sight of the American mainstream.В While global crossover Вartists like Shakira and Pitbull tend to define perceptions of Latin music, the most Вpopular Spanish-language genre in the United States is by far regional Mexican, a format steeped in nostalgia and bravado that accounts for 60 percent of the Latin radio stations monitored by Nielsen. вЂњThey are the gasoline of Las Vegas,вЂќ MuГ±oz told me in Spanish before the show. Of the 3,000 people crowded around the stage (who each paid up to $60 to get in), nearly all were of Mexican descent, and almost as many seemed to be employed in the tourist industry, from maids and cooks to Вlandscapers and construction Вworkers.