The gunpowder empires (also called land based empires) asserted their dominance over neighboring civilizations by using their massive armies (which was possible due to their massive land base) to invade neighboring regions.
the gunpowder empires also asserted dominance by wielding their tanks (that they had due to their massive amounts of gunpowder) to invade other regions.
These two assets of asserting dominance can be seen in the gunpowder empire of the Ottomans in their siege of Constantinople in 1453.