So it would work, but it's a hunting cartridge first and foremost. Thanks.
If you are using a floating chamber, then there are two problems: gas seal and seating.
>gas seal
There is a gap between the chamber and the barrel, just like in a revolver. CT seals it the same way the Nagant revolver does, that is, it fills the gap with material from the case. If the case is too short, then some of the gas will escape there, right into the action.
>seating
You have to hit the primer somehow, and for that to work it has to be in roughly the same place. If you are pushing cartridges with a different lenght into the action, and without adjusting the lenght they are being pushed, then shorter cartridges will just sit in the chamber too far away from the firing pin. Maybe you could construct the cartridge like in the Steyr ACR, and have a set of firing pins corresponding to all possible positions of the primer.
>But what if I'm using a more traditional action?
Then your shorter cartridges need to be either rimmed or belted.