Wrong.
That is NOT the bullet that is shown on virtually every published book and article. If you have that view of the bullet, then I assume you have the other views (such as the full view showing all the rifling marks and the bullet head? Can you print those, or do you just have this one? Also, the bullet you show is a larger caliber (even before the deformation) than the 6.5mm Oswald’s Mannlicher-Carcano was capable of firing. Look at the ruler and the bullet in your picture: That bullet looks a lot closer to .50 caliber than a 6.5mm.
I guess if that ruler is in centimeters instead of inches then it would make more sense.