Quality Dies Jacob's replacement Pellet Mill dies are manufactured from the highest quality steel forgings. Each of our dies are drilled by computer controlled gun-grills providing a smooth mirror-like hinished pellet hole. We offer 3 unique types of steel forgings, and also has the industry's largest inventory of steel forgings to ensure the fastest lead time. XTR Roll Shell Jacobs Corporation has developed the XTR roll shell to wear longer than other type of shell used today. The XTR shells are hardened to a depth of .180". The deepened hardness provides longer life by retarding the excessive wear that occurs when a shell is worn below the standard .030 depth of the competitor shell.