"Caliber" is the nominal diameter of the bullet itself, in inches. A .22 caliber bullet is 0.22 inches, a .44 caliber is 0.44 inches, etc. A 6.3 mm steel ball works out to 0.248 inches in diameter (.248 caliber)...but it's quite possibly 0.250" since that's a 'standard' size.
Prfesser

## Discussions

10 years ago

"Caliber" is the nominal diameter of the bullet itself, in inches. A .22 caliber bullet is 0.22 inches, a .44 caliber is 0.44 inches, etc. A 6.3 mm steel ball works out to 0.248 inches in diameter (.248 caliber)...but it's quite possibly 0.250" since that's a 'standard' size. Prfesser

Answer 10 years ago

thanks ps the ball is actually .328 to be precise but i didnt bother mentioning it

Answer 10 years ago

.328 inches, is not 6.3 mm, it's

8.3 mm. Either that's a typo, or you had trouble measuring.Answer 10 years ago

the steel ball from a bearing measured 6.328mm on a digital micrometer

Answer 10 years ago

Okay. So 6.328 mm (not 0.328 in). NM has given you the conversion factor, so you can do the math yourself, now and in the future.

Answer 10 years ago

. LOL That's what you get for giving him a fish. ;)

10 years ago

. For future reference, there's 25.4 mm per inch.