Remember When, The Naval Gun Factory

This was a time when the Navy could build it's weapons in-house, and on time. About 0:20 on part 2 notice the narrator mentions that the machine is capable of grooving liners up to 18"/47 caliber, that was the largest naval gun ever produced by the Navy in terms of caliber. Watch both videos, it'll be worth your while.
Part 1:

Part 2: