I already talked about this in Discord, but most of those reasons why they didn't become common had less to due to with problems of the weapon and more due to using individually loaded powder cylinders, something that Carrera does not use (it uses all-in-one rimfire cartridges). These percussion cap + powder chambers had issue of powder leaking and causing chainfire. Carrera does not use this system so it does not need to fear chain fire. Also, there are plates to protect user from cylinder gap blasts, which I note is used in modern Taurus rifles.Entire cylinder could be placed inside a sealed chamber in fact, thanks to use of all-in-one cartridges.
As for reloading, the best reload I could find for single-shot bolt-action is about 7 seconds from firing the weapon to the next shot. On a range, with ammo attached to the hand. Meanwhile for Carrera, developing moonclips is simple and easy and makes reload process last at best the same, while still providing ROF.
For the sustained fire, do remember that each time Reseph is loaded user needs to take the rifle off from their shoulder to process the bolt and rechamber it, losing the target and needing to take cover. In contrast, Carrera if it misses can simply operate the hammer with a finger and fire the second shot before enemy has had chance to take cover or return fire.
Also, it is incorrect to say that Carrera needs to reload all six rounds at one. It can only load one, two, three, four or five or indeed go for full chambering. It is matter of user. Breakaction is not actually that difficult to operate. Only thing I will give it over Reseph in that regard is that reloading takes slightly more space as you need to open up the chambers, but the needed space only matters if you are fighting in space that have you unable to move your shoulders.
Finally, hinge may be a break point, but it is not something that breaks easily. Once again I point to historical examples and how they didn't suffer this supposed problem.
Also, revolver actions allows us to easily revision a side-arm for our troops as well later develop gatling guns.
(Note: Those of you who already engaged me in debate on Discord, this is less aimed at you and more on those who were not there or are undecided)