I have both Rangoon oil (from H&H), and Young's 303. The Rangoon oil is definitely intended as a preservative. It has the consistency of a heavy oil. Doesn't have much lubricating ability, though. Smells much like Johnson's Paste Wax. I've used it a few times on some of my rifles, but I believe that modern compounds (like Eezox) are a better choice for serious rust-prevention.
As for the Young's 303, it's a cleaner, as well as, a lube. Works quite well removing fouling. Reminds me a good bit of Ballistol, just without the funky smell. Again, modern gun products would do a better job.