In 1967 I bought a Smith & Wesson .38 revolver and several boxes of ammunition. After a few visits to a firing range to learn how to use the gun, I put it and two boxes of ammunition on a shelf in my closet where they have remained ever since. I ran across them the other day and was wondering if the ammunition is still good after 38 years. If I tried to use it, would it misfire or blow-up?
It’ll probably work fine. At worst, you might have only a round or two misfire - that is fail to discharge. There’s no danger of it “blowing up,” though.
Take it to the range and use it there. It’s probably perfectly good, but I wouldn’t trust it in a self-defense situation. Or give it to someone who has a .38 and wants practice ammo. 
There was a case a few years ago of a man in Oakland who bought a gun for home defense in the 50’s, took it to the range a few times to practice, then put it under his bed until, a few years ago, somebroke into his apartment in the middle of the night. The guy was awakened by the intruder.
The ammunition still worked.
There should be no problems with it.
I’ve fired plenty of WW-II vintage ammo w/o problems of any kind.
Black powder era ammo might be an issue.
The only real concern is corrosive primers, but good cleaning after shooting will deal with that.
I might worry if the ammo was exposed to high levels of vibration. Burn rate depends on grain size.
Otherwise, if it looks OK it probably is.
As long as the cases show no sign of corrosion, you should be fine. I routinely shoot old shotgun shells, and some other centerfire ammuntion that my father-in-law has stored for many years. Much of that ammo is dated pre-1970.
I’ve found that much of it actually shoots BETTER than new factory loads that I can purchase today. Whether this is a case of better quality control then, better components, or simpler processes, I’m not sure.
I bought a case of old (1953) Soviet 7.62x54R ammo a few years back. Not a single problem with any of it.
1967 vintage .38 Special shouldn’t give you any problems corrosion wise. With ammunition, propellants get weaker with extreme age as opposed to stronger. One danger to be mindful of with real old ammunition is hang-fires where it takes a moment for the round to go off. If shooting real old ammunition (or even new I suppose), and it doesn’t go off, keep it pointed in a safe direction for minute before cycling the round out. You don’t want the round to go off while out of battery.
Good point, but you’re stuck in the autoloader paradigm. With a revolver (AFAIK there are no 38 SPL autoloaders) I’d wait a good minute, and then dump the cylinder quick as I could, rather than firing the remaing rounds.
Squibs are another potential hazard. If the propellant fizzles and the projectile is not fully expressed from the muzzle, firing another round will result in catastrophic damage to the weapon and possibly to you and others. A click is just a hangfire and is dealt with like UB suggested; a pop is something altogether different. After any unusual discharge, double check the barrel for an obstruction (but not by peering down the muzzle :eek: ).
As an aside, hang fires are also often caused by maladjusted/worn firing pins.
Excellent advice, sewalk. And apt.
Even modern ammunition can be dangerous if it was stored under extremely hot conditions. Smokeless powder can acidify under hot conditions which can make pressures erratic and dramatically higher than they should be. Acidified powder has a vinegar like smell that is different from normal. I was on an adjacent bench when my cousin shot some .223 ammo that had been stored in the cab of his truck for some time in Arizona. The acid smoke was so bad that my eyes started watering and the muzzle blast was so loud I thought at first he was firing a much more powerful rifle.
Old ammunition doesn’t automatically mean acidified but there may be increased odds it was stored poorly since it was made. The acidification problem is part of why the early M-16 had problems. The army knew that ammo would be stored in hot depots in southeast Asia so they switched to a powder that had a too-high percentage of calcium carbonate in the deterrent coating. This actually cause limestone deposits in the gas system.