As for original? I'd get a Webley Mk VI and shoot .45 ACP out of it. MAC on YouTube does this with his with no issues. Some say it can harm the gun but I'm not buying it. If it's good by MAC, it's good by me:
When Mac on Utube's Webley lets go, will you still be good with it??
The Webley Mk VI LOOKS like a big strong revolver. It is big, but not terribly strong. Standard .45ACP ball ammo is essentially proof level pressure for the Webley.
And while shooting proof loads is something a gun should survive, its not something that should be done as a regular diet, because, simply, there's no way of knowing HOW LONG that gun will survive. Might go thousands of rounds, might have the cylinder crack the next round he fires.
When the supply of .455 Webley ammo dried up, lots of them were shaved, to take .45acp brass, some were even shaved enough to take .45AR brass, but not all (I have one that won't).
What wasn't made clear back in those days, (or since, because people still do it) is that shooting .45acp ammo is too hot for the gun. The idea was to use .45acp brass (and clips) to give you something to shoot, loaded to WEBLEY CORRECT PRESSURE, which is less than standard .45acp.
There's a lot of broken Webleys out there, that lasted for years shooting .45acp ammo, until they didn't. If you've got one, do what you think best, but don't say that you were never warned about the risk.
I got to thinking about the top break, in general, and I believe there is no technical reason that a top break design in a high pressure cartridge could not be made. There are top break double rifles in 40,000psi cartridges, so obviously its not just the top break alone that matters.
What I think you can't do, is make a top break revolver that will hold up to a 40,000psi round, in a package that is an acceptable size & weight (and cost) to compete with solid frame revolvers of equal power.
No one has done it, yet, and as far as I can see, no one is trying to...