If ya ever get bored enough to do the math, 7.5 mm is .308 inches. 7.62 mm is .311 inches, a common bore diameter for the commies. Don't know why NATO uses 7.62 as a designation for .308 bullets.
No. 7.5 mm is 0.295. .308 is the barrel's groove diameter and the bullet dia., which measures 7.82mm(0.308"). The barrel dia. for the .308 is 7.62mm. That means the lands are 0.1mm(0.004") high in a .308 barrel.