Billy
Indeed there are.. The normal hunting rifle crown is a rounded affair with the center of the barrels thickness extending forward and both the rifling terminus and the outside forward edge of the barrel rebated. A target crown is sometimes created where a raised edge is left protruding in front of the barrel with the interior of the muzzle cut flat across to the rifling terminus. The 11 degree crown was developed as a way to, in theory at least, increase the evenness of the release of the popular 11 degree rebated boattails on some target bullets. It is just a tapering of the face of the barrel from the outside to the rifling terminus(bore) at an eleven degree angle.. There are almost unlimited variations on the theme but these are the most commonly seen. Regardless of what most might think their prime purpose is to protect the delecate rifling terminus. Damage to that can and will cause greivous accuracy problems..
