Please explain the difference between .38 and .380 (vanity)

2/16/03 | self

[rudy45]

I had always believed that the caliber of a gun was the inside diameter of the barrel. Assuming I am correct (am I?) then shouldn't .38 and .380 be "close"? If I remember from high school math, the latter simply implies a greater degree of precision. IOW, a .38 caliber really could be anything from .376 to .384, while .380 caliber has smaller variance--.3796 to .3804?

However, the attendant at a local range said that .38 refers to revolvers while .380 refers to pistols (?)

Thanks.

[cabincowboy]

More powder, same case, same bullet. More powder means more pressure when the bullet is fired. If your firearm is not designed to handle the higher pressures of +P ammo it is not safe to fire. The higher pressures of +P ammo place more stress on any firearm. +P ammo is typically used for defensive ammunition only. The difference in velocity between +P and standard ammunition is often as little as 50 fps, while it doesn’t increase velocity that much it increases chamber pressure quite a bit. There is also +P+ ammo, which few handguns are designed to fire.