Is 7.63 caliber a 32 caliber?

Answer 1

a .32 acp caliber pistol round is also called a 7.65mm in the metric designation. But that doesn't fit the real-world measurements, because a .32 pistol bullet is really more like .30 or .31 caliber, and 7.8mm in metric measurements.

The diameters of a 7.63 bullet and a .32 caliber bullet are similar, but that doesn't mean they're the same "caliber" or that they will fit the same guns.

The 7.62 mm family of rifles are often called ".30 caliber" and they really are close to that, with the bullets either .308 or .311 diameter.