I heard the same rumor back during the Clinton administration. It was not true then either. A five month shelf life would not be an on/off switch situation (i.e. at five months the powder suddenly stops working.) It would be a gradual deterioration that would mean weaker and weaker powder. This would lead to rounds stuck in barrels and barrels and actions exploding when the next round was fired.
No company would sell such powder because of the lawsuits. Besides those who still have guns (lost mine in a tragic boating accident) already have enough ammo for CWII.
>>esides those who still have guns (lost mine in a tragic boating accident) <<
If that had happened to me during my 1st marriage I would have had more guns and less alimony....