It will seal just fine up to a 4 or 5 inches or more I can't remember anymore. I do remember it being discussed when I went for training to be the company NBC N

It will seal just fine up to a 4 or 5 inches or more I can't remember anymore. I do remember it being discussed when I went for training to be the company NBC NCO. And it boiled down to appearances more than anything. Also special forces are expensive to replace and are out in areas that could have NBC related threats and have some of the biggest beards I've ever seen.