How to choose a door for protecting the house

Recently, many have set reliable metal doors to protect their own home. The installation of such a door must be very seriously. However, do not forget about choosing the door itself. How to choose good, reliable metal doors? First of all, it is worth knowing that they are divided into groups. The first includes doors that can withstand the effect of a hunting rifle and cold weapons. The second contains doors that can withstand 9 millimeters caliber weapons. The doors of the third group will be able to protect from shooting from a rifle or pistol «TT».Doors withstanding shots from hunting carbines or pump rifles belong to the fourth group. And in the fifth group there are doors that can withstand Kalashnikov’s assault rifle.