Before the .40 S&W, there was the .41 Action Express (AE). This was an earlier effort to put a .40 caliber bullet in a pistol designed for the 9mm. You only needed a conversion barrel for your 9mm pistol and (I'm assuming) a matching magazine.
The cartridge had a rebated rim to match the breach face and extractor of the 9mm, but the case and bullet was otherwise like the .40 S&W.
I had an EAA Witness 9mm (like a CZ-75, but made in Italy) that I converted to .41 AE long before there was any such thing as .40 S&W, back in the late 1980s. I just dropped in the conversion barrel. It's been so long ago, that I cannot remember if you needed a new magazine for it, as well, but if it was needed, I had one of those, too. Seems like that would have been a requirement, but I'm not sure.
The only issue was reliability. I'm not sure if this was common or not, but I quickly dropped the original 9mm barrel back in and gave up on the .41 AE.
