The P-39 Airacobra was other such aircraft, which fired a devastating 37 mm cannon through the hub. The space needed for the cannon also ended up requiring that the engine be placed behind the pilot, moving the center of gravity dangerously aft. With full ammo loads, it tended to tumble when stalled. But this configuration also made it very streamlined and responsive.A few, such as some versions of the BF-190, had a cannon that fired out of the center of the propellor, the engine being slightly offset from the gun and propellor. That eliminated the need for a synchronizer, of course, and also required no convergence adjustment.
It had a number of advantages and weaknesses. It was pretty thoroughly outclassed in the type of higher altitude engagements the U.S. and Britain fighters operated in, but the Soviets put it to very good use because the nature of most operations there were at low altitude were the single-state supercharger could breath.