sorry to prove your father wrong, the feedtubes are machines from solid billet. the porus part you are seeing is the material breaking under heavy stress, if it was a flaw you would see a clean break.
Originally Posted by L_x
Any doubts about the GT's feedneck can be put to rest with this video. There were 5 rotors attached and about 500 paintballs in them (seriously heavy) when I dove into the snake. Even just standing up shooting there was A LOT of pressure on the feedneck due to all the weight sitting back.