They're both measurements of the diameter of the round (or the barrel). Caliber is a measurement in inches, and millimeters are millimeters. For instance, a .30 caliber bullet is 30 hundredths of an inch, or 7.62 millimeters in diameter.
@ .05 inches
A type of ammunition.
air rifle
BBs are the ammunition used in BB guns. They are tiny, lead shot projectiles in the shape of a sphere. The name BB comes from the size of the ammunition, which is usually .177 caliber or 4.5 millimeter. The sizes of lead shot used in shotgun shells were B, BB, and BBB. This middle sized piece of ammunition in what gave the gun its name.
22 is a rimfire, 222 is a centerfire.
Given the limited information in your question I can only give a general reply. The caliber is the diameter of the rifle groove to groove in thousands of inches. So the difference would be .450" - .308" which equals .142". There are a lot of specified rounds of ammunition that use .308 and .450 bullets. In general the larger caliber bullet would also be more powerful.
It actually a type of ammunition. Instead of the firing pin smacking the center of the igniter cap, the rimfire ammunition is hit at the base. It is basically a wider percussion cap so you can not shoot high caliber bullets from them and they are only a one time use.
They are the same; just said in different order.
the 40 cal is a little bigger then the 357
.30 caliber.
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No