The country of Mexico is suing U.S.-based gun manufacturers, alleging the companies are actively facilitating gun trafficking to cartels south of the border. In a 139-page complaint filed in federal court in Massachusetts, lawyers for the plaintiff said 70 to 90 percent of guns recovered at crime scenes in Mexico were trafficked from the United States. Many were manufactured by one of six companies, all of which were named in the suit, authorities said. They are Smith & Wesson, Beretta, Century Arms, Colt, Glock, and Ruger. “Defendants design, market, distribute, and sell guns in ways they know routinely arm the drug cartels in Mexico,” the suit charges. “Defendants use reckless and corrupt gun dealers and dangerous and illegal sales practices that the cartels rely on to get their guns. Defendants design these guns to be easily modified to fire automatically and to be readily transferable on the criminal market in Mexico. …