Talk:Canon obusier

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"The canon-obusier was a smoothbore cannon using either shells, balls or canisters, and was therefore a vast improvement over previous cannon firing metal balls, such as the Gribeauval system."

The Gribeauval system cannons were smoothbore ones too, so can someone please add to the article WHY the canon-obusier could use more types of projectiles than the earlier one?