Nice old Remington built when Remington took pride in their work and before plastic and castings. Built by hand by skilled craftsmen from walnut and steel. Not some mass produced "modular" design. Modular is just a slang word meaning "so shotty that anyone with a screwdriver and a pair of plyers can work on it". These old guns were built when tolerances were so tight only skilled smiths with expensive machines could work on them. These are not the throw away guns built today. These were made to be used for many generations.