I am going to be the worm in the apple and say I don't feel the .380 is as reliable in older guns as the .32/7.65
This isn't quite as true when looking at most modern pistols such as the Beretta 84/85, the Sig 230 which was built around the .380 cartridge, or even the lowly Makarov which was designed to correct some faults the Walther pistols had in using larger calibers than .32 acp, extractor, feed angle, bad magazine design etc.
There are still some modern pistols that do seem to run better in .32acp than they do in .380
Erma handguns come to mind as do Bersa pistols, the .32s don't seem to wear out as quickly as the .380s
It could be that fewer .32s were/are sold than .380s and greater numbers usually add up to more noticable problems, my jury is still out on this.
Then there is the really pukey Smith and Wesson Sigma .380 but this gun was a dog in any caliber.
The S&W/Walther PPK pistols share the same faults as the original Walther PPK pistols and the few .32s on the market seem to run just fine while there have been numerous problems noted with the .380 caliber guns.
.380 is really a caliber S&W needs to stay away from,,,,,,,