Are 38 ACP aand 380 Auto the same? and can I size it with a 38 special die?

[Don1357]

I have about 100 cases of 38 ACP. Can I size it with a 38/357 die? I have no use for it but I have this compulsion of decaping/sizing all brass I have on hand if I can. Gives me something to do while watching TV.

[texassako]

.38 ACP became the .38 Super. Same case, but different pressure. I would not size it, or even decap it, unless you needed to use it.

[vzerone]

No 38 Auto and 380 are not the same. They are close in diameter and use the same bullet diameter. Probably where you may have got your confusion is that some ammo outlests refer to the 380 as the .380 Auto. The Colt 38 Auto was never referred to as 380 or .380.

As for the sizer question, yes 38/357 dies will resize the 38 Auto, but there is a specific reloading die set for the 38 Auto usually marked 38 Auto/38 Super. The 38 Auto brass is semi rimmed. The 38 Super is also semi rimmed, but it's becoming rimless now-a-days. The 380 is rimless. The case dimensions for the 380, 38 Auto/38 Super, and the 9mm Luger are different. The 38 Spcl/357 Magnum are too. The 38 Auto/38 Super and 38 Spcl/357 Magnum and .380 ACP are straight walled cases whereas the 9mm is not.

As and edited note the 9mm near the web of case has a larger diameter then the 38 Auto/38 Super.
You should just sell them if you have no use for them.

[JBinMN]

This is interesting...

I have always thought that the .380 ACP(Automatic Colt Pistol) & the .380 Auto(Automatic) were the same caliber & were just different names for the same cartridge. ( Only difference I thought was that Colt used the ACP , and the other manufacturers just used "Automatic" to avoid giving free advertising for Colt.)

I also believe that they are the same world wide.

Same as .45 ACP & .45 Auto. Always thought they were the same also.

Sure have never noticed any difference. I am gonna have to go look at some of my manuals & such. I have been loading them interchangeably, IIRC.

I am going to go look into this now, but without some verification I believe they are the same...

ETA:
Synonyms[edit]
9×17mm
United States — .380 Auto, .380 ACP.
European Union
Spanish and Italian — 9mm Corto / 9mm Short
French — 9mm Court / 9mm Short
Portuguese — 9mm Curto / 9mm Short
Dutch — 9mm Kort / 9mm Short
Bosnian — 9mm Kratak / 9mm Short
Western South Slavic (Serbo-Croatian, Slovenian) — 9mm Kratak / 9mm short, Kratka 9 (Kratka Devetka) / Short 9 (Short Nine)
Eastern South Slavic (Bulgarian, Macedonian) — 9mm Kas / 9mm Short
German — 9mm Kurz / 9mm Short
Romanian — 9mm Scurt / 9mm Short
United Kingdom — 9mm Browning, 9mm Browning Short, 9mm Short.

ETA2:

The .38 Super or .38 Super Automatic (C.I.P. designation) is a pistol cartridge that fires a 0.356-inch-diameter (9.04 mm) bullet. The Super was introduced in the late 1920s as a higher pressure loading of the .38 ACP or .38 Auto. The old .38 ACP propelled a 130-grain (8.4 g) bullet at 1,050 ft/s (320.0 m/s). The improved .38 Super Auto pushed the same 130-grain (8.4 g) bullet at 1,280 ft/s (390.1 m/s).[2] The .38 Super has gained distinction as the caliber of choice for many top pistol match competitors; it remains one of the dominant calibers in IPSC competition.

I did not think I was making a mistake in loading our .380 ACP/Auto.. I am glad I wasn't too.
;)

[vzerone]

Actually the .380 is the .380 ACP. Browning came out with it for Colt. There are a mind boggling amount of different 9mm's around the world!

[oso]

380 Auto Brass not the same dimensions as 38 ACP/Super Brass.
You could force 38 ACP/Super brass into a 38/357 size die with the right shell holder and decap but size it too small. Lube 'em first.
You could decap 380 Auto brass with a 38/357 size die using the correct shell holder but not size them enough for spec. Lube 'em first as the brass may have been fired in a large chamber.
I will disagree with vzerone and say that 380 auto is a straight wall case. Check the brass and decide for yourself. :grin:
P.S.
I do have good use for 38 ACP brass. Let me know if you are in a generous mood!

[vzerone]

380 Auto Brass not the same dimensions as 38 ACP/Super Brass.
You could force 38 ACP/Super brass into a 38/357 size die with the right shell holder and decap but size it too small. Lube 'em first.
You could decap 380 Auto brass with a 38/357 size die using the correct shell holder but not size them enough for spec. Lube 'em first as the brass may have been fired in a large chamber.
I will disagree with vzerone and say that 380 auto is a straight wall case. Check the brass and decide for yourself. :grin:
P.S.
I do have good use for 38 ACP brass. Let me know if you are in a generous mood!

oso...I had edited that mistake on the 380 Auto not being a straight wall case.

I load for the 38 Super and I use a set of 38/357Mag dies because a brand new set of RCBS 38 Super dies (NOS not their current new ones) and they size the case down too much. The cases sized with the 38/357 dies fall into my 38 Super chambers and I have 3 barrels BTW. One is an original Colt.

I suppose some of you know that you can shoot 38 Super's from most 357 revolvers, unless the one you have has particularly tight chambers. The rim will keep it from falling in the cylinder, in other words it head spaces. This does not apply to the current new rimless 38 Super brass. IMPORTANT NOTE: DO NOT SHOOT 38 SUPER AMMO IN 38 SPECIAL BECAUSE THE SUPER RUNS AT A MUCH HIGHER PRESSURE THEN THE 38 SPECIAL DOES!!!!!!

[Don1357]

I ran one through, it seems larger than 38 special. It took more effort and you can tell that the bottom part the die didn't touch is bulged/larger.


You should just sell them if you have no use for them.

But what if ten year from now I need them! :roll:


I do have good use for 38 ACP brass. Let me know if you are in a generous mood!

I got 205 of them, 103 nickel plated, 50 brass. Got any 44 mag or 45-70 you care to part ways with? :D

PM me, I got some odd sizes around such as 30 carbine.

[vzerone]

oso if you look on the SAAMI Spec's PDF you will see the 380 Auto has the measurements at the head of the case of .9739 and a measurement at the mouth of .9731 a difference of .0008 which is for all purposes a straight wall. The 357 Mag on the other had says "gives one measurement of .379 at the head end and the word cylindrical".

[smkummer]

I'll trade you some 380 brass for it.

[vzerone]

I'll trade you some 380 brass for it.

Consider the 38 ACP brass was not meant for 38 Super loads. Be wary. Yes I know you can load it down to 38 ACP specs.

[BK7saum]

38 acp and 380 auto are not the same and have different case dimensions. The most notable is the case length. The 38acp has a 0.900" case length. The 380 auto has a 0.680" case length. Different pressures/velocities and case strength.

[tankgunner59]

This is interesting...

I have always thought that the .380 ACP(Automatic Colt Pistol) & the .380 Auto(Automatic) were the same caliber & were just different names for the same cartridge. ( Only difference I thought was that Colt used the ACP , and the other manufacturers just used "Automatic" to avoid giving free advertising for Colt.)

I also believe that they are the same world wide.

Same as .45 ACP & .45 Auto. Always thought they were the same also.

Sure have never noticed any difference. I am gonna have to go look at some of my manuals & such. I have been loading them interchangeably, IIRC.

I am going to go look into this now, but without some verification I believe they are the same...

ETA:
Synonyms[edit]
9×17mm
United States — .380 Auto, .380 ACP.
European Union
Spanish and Italian — 9mm Corto / 9mm Short
French — 9mm Court / 9mm Short
Portuguese — 9mm Curto / 9mm Short
Dutch — 9mm Kort / 9mm Short
Bosnian — 9mm Kratak / 9mm Short
Western South Slavic (Serbo-Croatian, Slovenian) — 9mm Kratak / 9mm short, Kratka 9 (Kratka Devetka) / Short 9 (Short Nine)
Eastern South Slavic (Bulgarian, Macedonian) — 9mm Kas / 9mm Short
German — 9mm Kurz / 9mm Short
Romanian — 9mm Scurt / 9mm Short
United Kingdom — 9mm Browning, 9mm Browning Short, 9mm Short.

ETA2:

The .38 Super or .38 Super Automatic (C.I.P. designation) is a pistol cartridge that fires a 0.356-inch-diameter (9.04 mm) bullet. The Super was introduced in the late 1920s as a higher pressure loading of the .38 ACP or .38 Auto. The old .38 ACP propelled a 130-grain (8.4 g) bullet at 1,050 ft/s (320.0 m/s). The improved .38 Super Auto pushed the same 130-grain (8.4 g) bullet at 1,280 ft/s (390.1 m/s).[2] The .38 Super has gained distinction as the caliber of choice for many top pistol match competitors; it remains one of the dominant calibers in IPSC competition.

I did not think I was making a mistake in loading our .380 ACP/Auto.. I am glad I wasn't too.
;)

Actually the .380 ACP (Automatic Colt Pistol) is the designation of the pistol's themselves. The ammunition they use is designated .380 Aout (Automatic).