Yes, you could, but that’s still a massive blow to rate of fire, given that you essentially have to perform three actions to fire two shots. With manual bolting, you’ve eliminated fast-firing bolt-actions completely, and instead just made slow and slower weapons.
This also brings up the problems of firerate on other manually-operated firearms. What about slam-firing on shotguns? Fanning the hammer on single-action revolvers?
Now, it could be argued that manual bolting is akin to another mechanic, burst delay, however that is different in that without it, all burst guns would almost always be better than auto guns if you knew how to burst correctly. However, this mechanic is different in that you’re nerfing the underdog. Any chance that a player armed with a manually operated repeater has in close quarters against an automatic or even a semiautomatic weapon is all but gone as the player physically cannot do enough damage fast enough, unless of course the other player has potato aim and manages to miss an entire magazine.
Although the mechanic in of itself is more realistic, you really have to consider the implications this has on the overall meta. By including manual operation, you’re sending a message to every player that auto and semi guns are automatically (excuse the pun) better than a manually operated one. This in turn also affects how gunfights are going to work. Players with the superior weapon are now almost always going to rush the slower-firing weapon simply because they can deal out more damage faster, and this in turn brings up the problem of geared veteran players roaming around clubbing seals (new players).
Adding onto this, I have to question Nelson’s thought process when he decided to add this to the beta. Was it added to balance out high-powered sniper rifles? Was it for more realism? Or was this one of those mechanics that was added simply because it could be added? The only other games I’ve seen with this mechanic are hyper-realistic games such as Post Scriptum and Red Orchestra. Hell, even Escape From Tarkov doesn’t have this mechanic. Therefore, I’d like to implore Nelson to reconsider adding this mechanic to UII in its final form, as I believe that this would only have a negative effect on the game.
TL;DR, manual bolting would make semi and auto guns a straight upgrade over repeaters, a similar situation to how the Maplestrike is almost a straight upgrade over the Heartbreaker, which is why almost nobody would use the latter over the former, given the choice.