I buy surplus ammo when it is a good price, usually from individuals here on GBO. I just bought some 7.62x39 that I already had plenty of, but my son and I and our friends will shoot it up eventually. Is that hoarding? I don't think so even though I don't "need" that many rounds in the near future.
As far as rifles, I wasn't bitten by the Mil Surp bug until a few years ago when I bought a few of my deceased buddy's collection simply to help out his widow who is also a good friend. In reading just to see what I had, I got interested. I only had the SKS, Yugo Mauser and a Krag sporter up until the 3 Garands I bought last year. Ok, maybe I'm hoarding Garands? What can I say, they were each a good deal and couldn't pass them up.
Curtis