Rifle rounds will usually penetrate a Kevlar helmet.
They could make a helmet that is bullet proof up to a 50 caliber round, but it may weigh 350 lbs, require you to be strapped into a device and cost $75,000 each.
The larger versions offer complete body coverage, are priced much higher and are called "tanks",.
The larger version offers not only complete body cover, it would also cover you parents and children... just dont forget to leave your inlaws outside to wipe off bullet creases in the external panels...