In the bowl of a food processor fitted with the metal blade, puree raspberries, lime and lemon juices, sugar, and salt until smooth. Strain mixture through a fine mesh strainer into a large pitcher. Add tequila, Triple Sec, and Chambord, and 1 cup crushed ice to the pitcher. Stir until thoroughly combined and chilled. Divide remaining 1 cup of crushed ice between 4 or 6 margarita or double old-fashioned glasses. Pour margarita into ice-filled glasses; serve immediately.