The problem of having a follow-up shot has been around for a long time. It's the reason for squad and platoon marching and close order drill, allowing for groups to fire in rotation. It drove development of the brass cartridge. The revolving cylinder, still in use, was one answer.
And sometimes, the search took a turn down the development rabbit hole.
Here is the Bennett & Haviland Many Chambered Revolving Rifle.
same idea that lead to the revolver. Preload several chambers, then
move them into position for firing. The problem to be solved, as with a
revolver, is to ensure that the next chamber is correctly aligned with
the bore before firing.
Here's the example in the NRA museum. It is one of ten that were produced.