I was going to say Bergmann and Borchart, didn't know about the others on that list. The most successful was the Mauser, still being manufactured up into the 30s.
Had cylinders that were hand-loaded in a batch, then mounted for firing. You could have people re-loading "empty" cylinders while someone else was shooting it. It was a flintlock mechanism, but the firing process was repeatable. Loading each set of cylinders would be somewhat similar to loading magazines.
Regardless whether that's considered "autoloading" it shows that people were working on the possibility as early as 1700s.
The Collier Revolver was a similar technology flintlock revolver, but included a self-priming mechanism. That was the early 1800s.
As noted above, by the late 1800s, you can see the "same" characteristics that we associate with autoloaders.