I was thinking about porting the barrel on my 444S and asked a very knowledgable instructor at school and his response was "I would not even think about it unless I had an EDM to do it with. The small burrs inside the barrel are extremely dificult to remove and you can damage the rifeling trying to remove them." He also suggested the muzzle brake for a barrel that is not already ported or if you don't want to spend the money sending it out to someone with an EDM.