"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

9 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 9 years ago

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

Answer 9 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 9 years ago

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

Answer 9 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 9 years ago

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

9 years ago

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