I don't know...this "hoarding" explaination seems a little pat to me. I mean, 16 gauge 2 1/2" fiber wad shells? Who panic buys flats of those?
Other 16 gauge shooters :P
More seriously 16 gauge 2 1/2" fiber wad shells are probably a limited run product and currently ammo makers are too busy trying to catch up on standard loadings to do a limited production run. I shoot some odd handgun calibers and I don't expect to by able to buy more until Fiocchi and Prvi Partizan are able to catch up with demand