What is the definition of “Parent Case”?

[orpington]

May not be as simple of a definition as it seems. I’ll provide no additional discussion at this point and therefore the discussion will not be swayed by my potentially subjective statement(s).

 

[IWAC]

The case another caliber is made from. 7 X 57 Mauser=6mm/244 Remington, 257 Roberts; 30-'06, 25-'06, 338-'06.

 

[GRIZ22]

I've made 270 brass running a 30-06 into a 270 die. Shorter neck but I found no difference in accuracy.

 

[entropy]

Some might also define it as a case you can make another from, even though the "parent case" isn't a direct ancestor of the other. A good example would be 8mm Nambu made from .38 Spl. cases.

 

[Mr_Flintstone]

It has always been my understanding that the parent case is the basis for the development of a newer cartridge case having the same (or similar) basic dimensions except for case length and/or caliber; i.e. .38 Special is the parent case for .357 Magnum because .38 Special was the cartridge that inspired the .357 Magnum. Sometimes though, the listed “parent case” is actually the grand parent or great grandparent case. An example of this is .308 Winchester. Many online sources list .30-06 as the parent case, while it is actually the .300 Savage, which has a parent case of the .250 Savage, which in turn has a parent case of the .30-06 because that was their order of inspiration and development. Is it wrong to say that 30-06 is the parent case? No, but it isn’t very likely that the .308 Win would have emerged in its current form without the existence of the two Savage cartridges.

 

[Show Me]

May not be as simple of a definition as it seems. I’ll provide no additional discussion at this point and therefore the discussion will not be swayed by my potentially subjective statement(s).

What. A trick question?

 

[Show Me]

Daddy was .308. Mommy was .243
They had 6.5 Creedmoor and baby girl 6mm ARC. Baby girl is the runt.

 

[cfullgraf]

I dabble in at least one obsolete cartridge and a few wildcat cartridges and consider the "parent " case as the case I use to form the new case.

For forming 6.5x54 Kurz Mauser, i find 7x57 Mauser to work well as a parent case. 7mm-08 is acceptable and 308 Win or 30-06 can be used but these require case neck turning.

38/45 Clerke is made from 45 ACP cases. run the 45 ACP cases through a 38/45 Clerke sizing die, trim to length and load.

221 Remington Fireball can be made from any of the full length 222 or 223 Rem cases but I find 222 Remington works best.

In the beginning, I made lots iof 300 BO case from 223 Remington. Size, and trim the cases., I found I did not need to trim the case necks, It is nice that factory ammunition is available now.

7mm-International Rimmed is made from 30-30 casesl Run them through a 7mm-Int Rimmed die and then fire form them.

In most cases of new cartridges, firearms manufacturers start with an existing case and modify it for their new cartridge. Generally, it seems, the case head is the determining factor and the body and neck are changed as desired from the cartridge designers. Changing the case head from an already existing design probably requires more expensive tooling for the new cartridge (this mechanical engineer's production consideration).

 

[orpington]

I ask this because I always considered a parent case to have an identical head and rim and be longer than the next generation of rounds developed from it, or nearly so, to which any next generation rounds could be sized using the parent case.

But someone in another thread suggested, indirectly, once you create a neck on a straight wall case, it’s no longer an offspring. For example, .40-65 being straight walled would have a parent case of .45-70, but this would not apply to .38-56 and .33 Winchester, as they are bottleneck cases. Now, I know this to be flat out incorrect.

But it got me thinking about this. For example, .30-06 Springfield is the parent case of several other rounds. It is 2.494” in length. Two such rounds of which it is the parent case of are .250/3000, with a length of 1.912”, and .300 Savage, with a length of 1.871”.

Wikipedia gets a lot of things wrong. It lists the parent case of .300 Savage as being .250/3000, which is, of course, incorrect, as it’s still .30-06.

And, technically, ALL of this is incorrect, as there is a parent case of the .30-06 Springfield, this being .30-03 Springfield. And such, this should be the parent case of .30-06, as its length is 2.54”.

But what if .250/3000 had been developed before .30-06? Would it be the parent case simply because it came about first with identical head and rim dimensions, or would it be impossible to be stated as the parent case because it’s impossible to create a .30-06 case using .250/3000?

As one can see, the definition of parent case is not as straightforward as one might intuitively think.

And, lastly, what about base diameter, rim diameter, and rim thickness differing from the parent case. Then is the parent truly a parent case as it’s possible due to these differences, the formed round from the parent case doesn’t function in the firearm as intended? And why create these subtle differences to begin with?

I’ll close with the base diameter, rim diameter, and rim thickness of all the rounds discussed above so you can see the subtle differences:

.30-03 Springfield (1903):

Base diameter: 0.470”
Rim diameter: 0.473”
Rim thickness: 0.045”

.30-06 Springfield (1906):

Base diameter: 0.471”
Rim diameter: 0.473”
Rim thickness: 0.049”

.250/3000 Savage (1915):

Base diameter: 0.469”
Rim diameter: 0.473”
Rim thickness: 0.049”

.300 Savage (1920):

Base diameter: 0.471”
Rim diameter: 0.473”
Rim thickness: 0.049”

Of course, we commonly accept the parent case of .250/3000 Savage, for example, as being the .30-06, and yet the base diameter differs from the .30-06 slightly. The base diameter, rim diameter, and rim thickness of the .300 Savage round is identical to the parent case of .30-06. And yet, its parent is listed as .250/3000. Which is confusing in itself, as one would be much more inclined to create .300 Savage from .30-06 than from .250/3000.

 

[Ohen Cepel]

I never thought that the rim/head of the case had to be the same as some are turned down as part of the conversion process.

 

[Mr_Flintstone]

I have spent the better part of the morning using my best Google-fu to find an accepted definition of “parent case” or “parent cartridge”, but have been unable to do so. Even SAAMI and C.I.P do not have a definition of the term, although they do mention the term in describing the lineage of cartridges.

There does seem to be some consensus that a parent cartridge serves as the “basis for the development” of a new cartridge, but no hard definition of what that means. As stated earlier, many parent-offspring cases share common characteristics such as rim diameter, case diameter, etc…, but I don’t think they necessarily have to. As a matter of fact, .45 acp is sometimes stated to be the parent case of .380 acp, not because they share any dimensions, but because J.M.B. reduced the dimension proportions of the .45 acp to 78% overall in creating the .380 acp. Other times, the .38 acp is stated to be the parent case of .380 even though they differ in rim, bullet size, and case dimensions.

So, I’m adjusting my definition to simply say that a parent case is what serves as a basis for the development of a new cartridge.

 

[.38 Special]

It's pretty simple, for me: a parent case is whatever was used to make the current case. If you necked it down or up, or shortened it, or turned the belt off, you've got a "new" cartridge, and the parent case is whatever the headstamp says it is.

The only complication is that a parent case may have a parent case itself, and then what do you call it? A grandparent case?

I've solved the whole issue for myself by simply not thinking about it.

 

[GeoDudeFlorida]

It has always been my understanding that the parent case is the basis for the development of a newer cartridge case having the same (or similar) basic dimensions except for case length and/or caliber; i.e. .38 Special is the parent case for .357 Magnum because .38 Special was the cartridge that inspired the .357 Magnum. Sometimes though, the listed “parent case” is actually the grand parent or great grandparent case. An example of this is .308 Winchester. Many online sources list .30-06 as the parent case, while it is actually the .300 Savage, which has a parent case of the .250 Savage, which in turn has a parent case of the .30-06 because that was their order of inspiration and development. Is it wrong to say that 30-06 is the parent case? No, but it isn’t very likely that the .308 Win would have emerged in its current form without the existence of the two Savage cartridges.

Inspired by is different than made from. The .250-3000 Savage may have been made from the .30-06, or .30-03, or .30-45, which were themselves inspired by the Mauser small-ring action cartridges - specifically the 7x57mm Mauser, but made slightly larger in some key dimensions to avoid patent infringement claims; so the American versions were not made directly from any of Mauser cartridges but the inspiration and links were close enough for courts to conclude that the US had indeed violated Mauser’s patents, several times.

An Official Journal Of The NRA | The M1903 Springfield: A Look Back

Staring out as a patent rip-off of the 1898 Mauser, the M1903 Springfield remains a popular rifle to this day.

www.americanrifleman.org

The interesting thing about this topic is, trying to find the line between inspired by and made from. I tend to think inspired by is historical while made from is mechanical. But they both indicate lineage which doesn’t necessarily mean parentage.

Good topic. Not sure where the distinction is in reality.

 

[mm93]

Parent case is the case later similar cases with the exact same rim and base diameter all came from.
Donor case is the terminology for cases we use to form brass for obsolete cartridges we form to different cartridges.
I form .40-63 Ballard from .405 Win. cases
.40-50 Sharps Straight from .303 British, or .30-40 Krag.
.44-77 BN from .43 Mauser
.40-85 Ballard from 9.3x74R
.32-40 from .38-55 or .32 Win Spl.
9.5x47R from .38-55
Others also, but too many obsolete I make to go on.

 

[mdi]

In "Handloader's Manual Of Cartridge Conversions" listed are hundreds of cartridge conversions This text uses a bit different "parent case" nomenclature as a simpler "make from". Same meaning K.I.S.S...

 

[Mr_Flintstone]

I think we’re getting into the old magazine or clip argument here. There are enough problems in the world. We don’t need to invent things to argue about

 

[Rule3]

How the want to list parents on BC now.

Parent One
Parent Two

Whatever the case was developed from

 

[Rimfire McNutjob]

Daddy was .308. Mommy was .243
They had 6.5 Creedmoor and baby girl 6mm ARC. Baby girl is the runt.

I'm pretty sure mommy was sleeping with Mr. 30 T/C and Mr. 308 just doesn't realize that 6.5 Creed and 6mm ARC aren't his kids.

 

[GeoDudeFlorida]

I think we’re getting into the old magazine or clip argument here. There are enough problems in the world. We don’t need to invent things to argue about

Yes, but it beats yet another, “Can I use lead data with jacketed bullets if’n I squint real hard?”

 

[Show Me]

Where's the argument, this is good stuff

 

[Bazoo]

A parent case is the case from which another case is based upon. It can be the basis of forming a new case, or have some of the dimensions for a new case even if the new case can't be formed from it due to length or or rim configuration. So a 222 Remington is the parent case of a 223 as well as the 222 Rimmed.

 

[GeoDudeFlorida]

A parent case is the case from which another case is based upon. It can be the basis of forming a new case, or have some of the dimensions for a new case even if the new case can't be formed from it due to length or or rim configuration. So a 222 Remington is the parent case of a 223 as well as the 222 Rimmed.

I can agree with that. The parent case for the .22Jet is the .357Magnum (descended from the .38Long Colt -> .38Spl) but it was inspired by the .22WMR.

 

[Menace2]

If modifying a case to make a new case for a different cartridge, then the parent is the case you are modifying.
If looking for heritage, it would be like all the modern family of .472 rimless cases started with the M88 Patrone/Commission 88 case, also called 7.92x57/8mm Mauser/8x57 (whichever you use without getting into a silly fight over the name of the same cartridge) is parent case to 7.63x53, 7x57, 30-06 and etc. etc.. etc.
I make 219 Donaldson Wasp. My parent case is 30-30 Winchester. However, Mr. Donaldson started with 219 Zipper, so that is the historical parent case.

 

[GeoDudeFlorida]

If modifying a case to make a new case for a different cartridge, then the parent is the case you are modifying.
If looking for heritage, it would be like all the modern family of .472 rimless cases started with the M88 Patrone/Commission 88 case, also called 7.92x57/8mm Mauser/8x57 (whichever you use without getting into a silly fight over the name of the same cartridge) is parent case to 7.63x53, 7x57, 30-06 and etc. etc.. etc.
I make 219 Donaldson Wasp. My parent case is 30-30 Winchester. However, Mr. Donaldson started with 219 Zipper, so that is the historical parent case.

I make 9mm Makarov from 9mm Luger. They aren’t related, not even close. But it works.

 

[HowardC]

So, are my Ackley cases "child" cases of 25-06, 260 Rem and .223? Like the 270 or 30-06 cases I used to make 25-06 Ackley, or 7mm-08 and 308 cases used to make 260AI? Or, does the 'parentage' go back further?

-West out