I have 2 PASGT replicas - one in ABS, and another made from fibreglass. I also have the CF issue Gallet helmet. Doesn't matter which one gets shot, it resonates like a mofo, although the fiberglass and kevlar ones resonate less than ABS. The Gallet helmet is actually the best, and I think that's just the nature of the padding inside that muffles the sound more. I don't have any suggestions that are better than what's been given here already.