Most people think that breechloading arms began with the development of paper or brass cartridges, but this is not strictly true. While not common before that period, there were gunsmiths here and there experimenting with breechloading systems hundreds of years before they became commonplace. The British Ferguson rifle is an example of one that did see some limited production, but even earlier we see examples like this gorgeously embellished 1625 wheel lock. It uses a simple steel cartridge case that would be pre-loaded with powder and ball, and then dropped in through the Snider-style trap door at the breech of the rifle. It is also equipped with relatively nice sights for the time and double set triggers – whoever commissioned this weapon was clearly a serious firearms enthusiast!
You can see another very similar example here – note that it was missing the cartridge which I did not recognize at the time, but you can see the notch where the cartridge’s indexing pin would fit.
Note: The gun in this video was pulled from the RIA auction after I did my video – not sure why, but probably a conflict with the consignor over value estimate.