I believe you are thinking of a revolver cannon versus a rotary cannon. In my imagination, the installation would have multiple barrels protruding through the engine hub. Yes, I know that is its own issue, but hey like I said before, facts be damned.what I am referring to is if the cartridge doesn't go off exactly when the primer is hit (or electrical impulse hits primer).
On most of the modern all the barrels are exposed. If the cartridge goes off partway to the next station (before the extractor moves it very far? the shell exits the gun a little off center and there is little harm done. But if you are depending on all the shells to go through a tube only a few mm bigger than shells and and you get even a 1 in 10,000 chance slight delay where does the shell go?
This is one reason why the Germans stopped trying to put big 30mm cannon in synchronized positions Like wing roots of FW 190s. The shells exit from the barrel varied to much from when the firing pin or electrical impulse hit the primer. This was worse with the bigger cartridge cases and unless you were trying to synchronize to a propeller with fixed gun or using a rotating gun in a tube it is not a problem. Cartridge goes off a small fraction of second late in the fixed barrel gun, the gun still cycles a fires again. Most shooters may not even notice.