Actually, the French were trying to produce it as early as 1806 and experimented with it. Apparently there was a limited production run but it seems to have fizzled out. I don't know the reason why. Perhaps, and this is just a guess, they might not have been able to get an airburst from the available fuses. That is the only reason I can think of for them not developing the round in quantity. As spherical case shot was an explosive shell full of smaller balls, the only thing that wouldn't seem to work properly would be the fusing as the French did employ explosive shell.