.38 vs .380 -- differences?

[Effingham]

This is an embarrassing question... but I have to admit that I don't really understand something about ammo.

I've got 9mm and .22s here, but the question is on .38 ammo.

Is there any difference between .38 and .380? The mathematician in me maintains that they're exactly the same thing, but the fact that people make that distinction in guns implies to me that they AREN'T the same. As one who's never owned a .38 (or .380) shooting gun, can someone enlighten me about this?

Like I said, it's an embarrassing question, but I've always wondered...


Tony

[VERT]

.380 generally refers to a cartridge used in a .380 semi automatic pistol. The cartridge is also referred to as 9x17 or 9mm Kurt (short). Common guns that use this cartridge are the Walther PPK, Walther PK380, KelTec .380, Ruger LCP, Sig P230/232, Beretta 84, Bersa .380, etc.

.38 is usually referring to the .38 special revolver cartridge. Think snubbies or Smith & Wesson model 10.

Now is the question to compare these two cartridges? .380 is commonly loaded with a 90 - 102 grain bullet. .38 Special is commonly 110 - 158 grain. Depending on the barrel length the .380 in an auto will provide more velocity. I personally consider the .38 special in a snub or .380 in a medium sized automatic to be the minimum for a self defense handgun.

[armedindy]

whoa, i didnt know .380 had more velocity..interesting. but .38 sp has more penetration because the bullet is so much heavier i beleive...?someone help us out

[canamscott]

Here is a very general way to keep it straight. Usually the first two numbers are the measurement of the barrel diameter, therefore .38 inch. Whatever follows that is a modifier that refers to the shell casing.

Example; .22s, .22lr, .22 mag. Each is a .22 caliber bullet, but three different casings and different powder loads. But that different powder can translate into capacity for a heavier bullet.

So a .38 special and .380 acp could use the same bullet, but the difference in brass has different powder capacities, different chamber retention, and different extraction. It is common usage to consider the extra 0 on .380 as the modifier to keep them straight from each other.

That is why it is critical to know what your firearm chambers and get only that. Here is a link to a cool poster that compares contemporary cartridges in common usage, 140 rifle and 41 handgun.
IHEA Store, Cartridge Comparison Guide Special Pricing

There are a few exceptions to this rule, but a rule of thumb is a good place to start.

[VERT]

Originally Posted by armedindy

whoa, i didnt know .380 had more velocity..interesting. but .38 sp has more penetration because the bullet is so much heavier i beleive...?someone help us out

Depends on barrel length and load. So evaluate my original statement with some discretion. But yes factory .380 out of an automatic with a 3.5" barrel has more velocity then a standard .38 special out of a 2"-4" barrel. As barrels get shorter a person loses some bullet velocity. This is one reason why the discussions about whether a person should carry FMJ or HP bullets in their micro, mini, pocket, mouse gun. .380 is a somewhat marginal round to begin with and when you stick it in a smaller gun....there is the question of how or if a hollow point bullet will expand.

Yes .38 special is heavier. Bullet weight & velocity both figure into muzzle energy.

[XtremeVel]

(2) totally different cartridges !

.380 = .355 dia bullet... Same as 9mm, just lighter weights...

.38 = .357 dia.... Same as you would use in .357

[Classic]

For a more detailed look, go to any of the major handloading sites and look at their loading tables. Some of them compute muzzle energy (a function of bullet weight and velocity) that should be useful for your question. My old paper copy Speer Number 9 manual shows a maximum muzzle energy for a 38 Special 344 ft/lbs, using a 160 gr softpoint and 9.9 grains of 630 powder at 944 ft/sec. The maximum muzzle energy for a 380 is 223 ft/lbs of muzzle energy, using a 100 grain hollow point and 4.4 grains of Unique powder for 1004 ft/sec. Of course there are many other factors to consider like how the energy is transferred to the target, hardness of the target, etc.

[XtremeVel]

.380 doesn''t have to contend with losing a little velocity from the cylinder gap such as a .38... Along with lighter bullets, this doesn't shock me...

I don't know, but is .380 also considered a high pressure round being it's case capacity is so small ????

[Effingham]

This is fascinating. Thanks for all the explanations.

I admit to being a bit nonplussed that .38 = .357. So why do we even make the distinction? (In addition to this just being mathematically and logically WRONG on so many levels....)

[VERT]

Originally Posted by Effingham

This is fascinating. Thanks for all the explanations.

I admit to being a bit nonplussed that .38 = .357. So why do we even make the distinction? (In addition to this just being mathematically and logically WRONG on so many levels....)

To be honest I am not sure why they call it a .38 special instead of .36 special. Marketing I suppose. I am sure somebody will be along shortly with the history lesson. But .38 special is different then .357 magnum. The difference is in the length of the case itself. Hence why a person can shoot .38 special in a .357 magnum revolver.

Oh and don't confuse .38 special with the other .38 revolver cartridges out there. One example would be .38 Smith & Wesson. Different cartridge!