.38 Special vs. .380 ACP

38 Special vs. .380 ACP
Original Post:
I am familiar with the 38 cartridge, but the 380 is new to me. Can some kind soul tell me about the 380?
While I am at it, what does the second number in some rifle cartridges stand for? For example 7.62mmx39mm.
Thanks in advance.

Reply, less than one hour later:by UJ2744e - "Visual Posts" Moderator
I give you the "short form" to start with.
First the .38 Special:
Rimmed (meaning rim sticks out beyond major case diameter) - therefore most suitable for revolvers. Case capacity - large enough to launch up to or about 158 grains at useful velocities.
Pressure - Low, due to very long duration of existence. Newer firearms with improved metals may use a slightly higher pressure rating known as "+P" in the same case.
Projectile Diameter: either .357" in jacketed or .358" in lead.
Then the .380 Auto:
Rimless (meaning the rim does not stick out beyond the major case diameter) - therefore most suitable for semiautomatic pistols.
Case capacity - large enough to launch up to about 100 grains at useful velocities.
Pressure - Low, due to long duration of existence. This is about the most recoil a cartridge can produce and still be used in a "blow-back" handgun action similar to a 22LR.
Projectile Diameter - .355 in jacketed or .356 in lead (this is 9mm)
Next, "names":
The metric method of designating cartridges is done by first stating the diameter of the standard projectile in mm and then the case length in mm. It is a "general" method of designating military cartridges that gives a quick ID of caliber and overall "power" level as indicated by how long the case is.
Here are few examples:
The Russian 7.62X39 uses a 7.62mm projectile in a 39mm length case.
The NATO 7.62X51 uses a 7.62mm projectile in a 51mm length case. This is known commercially as .308 Winchester in the USA.
The 9mm Luger is also known as the 9X19
The .380 Auto is also known as the 9X17
A decent reloading manual from a major bullet manufacturer such as Sierra, Speer, or Hornady should have this kind of information in it.
I hope this is helpful.

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Well, that's all for today, my friend. If you do decide to take me up on the 7-Day trial before Friday, please consider using this direct link to this ".38 Special vs. .380 ACP" thread on our forum, if you want to add to the discussion. Hope to see you around!
Tim SchmidtUSCCA - Owner / Founder