Congtrats! you just made a pipe bomb! And one that isn’t as good as a steel pipe You do understand that PVC pipe would not be able to contain the pressure of even the most anemic cartridge don’t you? Even a 1" schedule 80 PVC can only contain up to 520PSI @ 73F. Modern Cartridges easily generate 12,500PSI for a light shotgun target load of birdshot.