Sultan Selim I (1512-1520) was the first Ottoman Sultan to use the title Caliph. So if you are going by that then okay it is about 410 years as "caliphate", but it really is just a nominal distinction, considering Mehmed II was viewed by many at the time a Caliph.
Selim I - Wikipedia, the free encyclopedia
The Ottoman dynasty was already an empire even before conquest of Constantinople in 1453. In the first 150 years they had already conquered parts of eastern Europe. In 1350, Ottomans had begun making advances into eastern Europe, in 1362 they captured Edirne, 1389 Battle of Kosovo, and 1396 capture of Nikopol which completed Ottoman conquest of much of Thrace and Greece.
That's true Sultan Selim I conquered Egypt in 1517 and defeated the Abassid/Mamluk "caliphate".