"but that's going to be a mighty odd looking revolver"
That kind of goes without saying for a low-set barrel design of any type.
The trick for ejection is to have the fixed portion of the frame supporting the barrel pivot have a couple 'gear teeth' that will drag the ejection rod backward as the barrel rotates downward. Same basic principle as any other ejecting break top. By utilizing spring loaded ejection (think O/U shotguns) in conjunction with positive mechanical force, the need for full ejector rod travel is unnecessary. My tentative design swings out about 100 degrees if memory serves (but is cushioned by the ejector/latch springs at each extent, so it can be flipped open/shut more violently)
I alluded to this earlier, but revolver design is much more spatially complicated than for semi-autos. The simultaneous functions and motions of practically all moving parts, and the non-planar shapes of the structural frame elements make for a design problem somewhat like 3D chess in comparison to semi-autos that can be sufficiently described with a simple cutaway profile drawing along the bore axis (in most cases). Cams are always hard to design, and basically everything in a revolver runs on them.
I
think a design could be produced easily that has essentially a funky looking machined/forged barrel trunnion/upper frame which nests into a simple channel-shaped lower receiver, to which the grip/trigger group attach. But break-top revolvers are expected to do so much more than SA or even DA revolvers*, that there are inherently a
ton of small parts that have to be developed. I think the design could be useful, but would be a wildly expensive and finicky undertaking. I think it mostly serves as an entertaining and difficult design experiment.
One last bit; there's a guy on weaponsguild making a break top "Samaritan" revolver in 4x20ga (DD) with a cylinder about the size of a naval orange. I
believe he got the double action trigger, cylinder, and latch more or less completed before backburnering the design (very common among gun builders) for a later date. The shear size of the thing means it is probably strong enough, but I have to think that 20ga is probably more load than any break top revolver has seen to date
TCB
*I love how it's just
expected that an extremely complex mechanism to eject shells automatically is incorporated simply because the gun locks closed a certain way, and a few famous designs did this (and greatly reduced reliability in doing so). It's also expected that the design be SA/DA just because; a hammerless DAO would be way simpler, and honestly, probably more useful if speed is the need.
