Incidentally, there is a modern semiautomatic revolver that is still in production. Produced by Mateba in Pavia, Italy, it is a rather blocky looking handgun. It also features an inter-changeable barrel , and fires the bottom cylinder (as opposed to the top one in most revolvers; much like the weapon in the anime Trigun).
I happen to own the .357 Magnum version (Model:Unica6), which also fires .38 special bullets, albeit in non-semiautomatic mode. This is due to the recoil of the .38 special being too feeble to cycle the mechanism, which makes it function like an ordinary double action revolver. It is also available in .44 Magnum.
In semi-auto mode firing .357 Magnum, the recoilless gun IMHO to at least 1/2 of what it would have been. This is because the top half of the gun, with the exception of the handle, hammer and trigger mechanism, slide back from the recoil of each shot, softening the impulse transferred to the user. It also allows six shots to be fired off in rapid sucession without missing a a tactical "human-shaped" target at 25 yards. A typical spread is about 4 inches at 25 yards.
It retails for anywhere between $600 to $1000 or more depending on its caliber, barrel length and accessories.
Ping me if you are interested in finding out more!