Turbinato sugar does not dissolve very well. That's why I hate it when it is the only sugar offered in coffee shops. Even in hot coffee it has to be stirred a long time to get it to dissolve, and even then, the bottom of the cup is always way too sweet after not tasting very much of it at the beginning. Your bottle bombs are probably from the bottom of your bottling bucket. Most of your beers will probably be flat.