Well, sometimes it's a plus...I have NEVER walked in and asked for a couple of boxes of ammo and had the person behind the counter say, "Don't have any, the Sherriff's Department bought all the .41 Magnum we had". Now, stocking up to shoot the 9mm around here can keep you driving from store to store for a while.
And "herohog", that has GOT to be one rare gun...I have been trying to find an AMT Automag in .30 carbine for a long time. At the moment, I can't remember ever even hearing of 9mm WinMag!