I have read a few articles on M4s and M16s in the Army and Marines having safety selector issues. Namely the rifle will AD or ND with the safety on. I have never seen or heard of this. I never saw an M16 have a safety issue in my Marine days. The one article stated 6% of the rifles needed to be fixed. Seems like an incredibly high number. Anyone actually experienced this or does anyone know what the problem really is?