>>580672
Actually, you could probably add a lever to the design shown in OP's picture, and remove the sides of the magazine well. With a proper locking mechanism, and not-shit alignment you could probably build a real shitty kind of rotating revolver magazine holder that allows you to switch from one magazine to the next.
The lever first lowers the revolver mag assembly to clear the bolt carrier even on a closed bolt.
It then engages a cog which rotates the magazine assembly. Releasing the lever will only raise the assembly. It would need quite a strong spring that pushes it up, because the spring in the magazine would work against it if the bolt is closed.
I know this is retarded, but it would be a neat little toy with no real use.