Question: What is the trigger pack on the Colt 602 with the A1 rear sight type? 
SQL: SELECT "Trigger pack" FROM "1-19901-1" WHERE "Rear sight type" = 'A1' AND "Colt model no." = '602';

Question: How many case deflectors are there for the Colt 646? 
SQL: SELECT COUNT("Case deflector?") FROM "1-19901-1" WHERE "Colt model no." = '646';

Question: What is the rear sight type on the model with the ACR muzzle brake device? 
SQL: SELECT "Rear sight type" FROM "1-19901-1" WHERE "Muzzle device" = 'ACR muzzle brake';

Question: Which muzzle devices are on the Colt 603? 
SQL: SELECT "Muzzle device" FROM "1-19901-1" WHERE "Colt model no." = '603';