Slamfire said: "Gunpowder lifetime is the limiting factor for ammunition lifetime. Lifetime expectancy for single based powders is 45 years and 20 years for double. High heat and bad storage conditions can reduce this life time to months."
You, sir, are the only one I ever see posting that. Either you are right and a few hundred thousand of us are totally wrong, or your information is not really applicable. There are differences in how ammo is made today compared to before the 1950's, and so the stories of old British 303 ammo deteriorating, etc are probably true, but one does not see the same stories about ammo from the 1950's, 1960's, 1970's, etc. By your estimation, double-based powder ammo from the early 1990's would be unsuitable for use today, and yet many of us, probably most of us, have fired rounds from the 1970's that were just fine. Many people have fired rounds from way before the 1970's without any problems. And, there are numerous stories of guys keeping ammo in un-air-conditioned garages in southern states for decades without problems.
So, like I said, maybe you are right, and the rest of us are totally wrong. Maybe. Maybe not.