When my Dad passed recently, I inherited his .380 pistol and stash of hundreds of rounds of .380 ammo that he bought 20+ years ago, still in the factory cardboard brick boxes on his closet shelf...but never used, because health problems disabled him shortly after.
We both had identical .380 pistols and it was time to play with my new Ronin & Saint Edge, as well as exercise the rest of my guns...so off to the shooting range I went with everything I had, as well as Dad's .380 ammo & .380 pistol.
Every 3-4 rounds of his .380 ammo jammed in his .380.
So I tried them in my .380 and they also jammed every 3-4 rounds.
It was consistent, regardless of which gun used or any of the several identical mags I used in either pistol.
After examining the ammo closely, I saw that the brass cases were no longer as shiny & new looking as they used to be, but had a very fine oxidation on them...just enough to cause jamming, I'm guessing.
Since the ammo is jamming, it's not really usable, unless I find a way to clean the brass cases...which would be a PITA to do by hand.
(I'd be thankful for any suggestions how to clean the ammo.)
On another note, the Ronin & Saint Edge were butter-smooth and accurate right out of the box. I have many .45's...but the Ronin is the finest & smoothest one of the bunch. The Saint Edge was also great. SA hit a home-run on both.