As previously mentioned, a marksman for Remington shot 100,000 wood blocks with this model of gun, but he used three different rifles, shooting about 33,000 rounds through each. The stunt was to show how durable the gun was. I believe I read the Nylon 66 was designed to last 75,000 rounds. As I recall, even the receiver was nylon on some versions, but Remington ended up sheathing some of the plastic parts in metal so that the gun buying public would have more confidence in it - purely cosmetic. I think there was a similar model that followed it - the 77 maybe? - that was matte black. It may be more affordable than the 66.
The guy who first got me interested in buying a rifle when I was 18 had one of these Remingtons. Like the OP, I can't for the life of me figure out the cult like appeal that they have.