Talk:Delta L problem

Unsafe combinations and Delta L problem

Hi Francis (and others). I am looking in more details at the -- Unsafe combinations -- paragraph in the C.I.P. article. If we take the .30-06 Springfield for example, we see the dimension we call L2 is 2.109 inches (53.569 mm). This value given there, is it the SAAMI value ? Is it the maximum length ? CIP gives 56.560 mm for the maximum. There is 9 µm difference, do you know where this difference is coming from ? --Michel Deby (talk) 11:03, 12 January 2008 (UTC)

Hi Michel,

I get the impression you think I am a US citizen, but actually I am from Europe. In daily life I sometimes have to deal with C.I.P. decisions/standards, when handling rifles in one of the C.I.P. member states or discussing sports and hunting arms with friends living in C.I.P. regulated countries. I can not help on L2 differences between the .30-06 Springfield article drawing and C.I.P. drawings/tables. Cartridge drawings in Wikipedia will be uploaded by Wikipedia contributors. I also uploaded some unofficial cartridge diagram drawings, but can not guarantee their correctness (like everyone I can make mistakes, C.I.P. can decide to change dimensions etc., or other editors can change things without me knowing). As a minimal safeguard I tend to add links to the current online version of the C.I.P. decisions, texts and tables on the C.I.P. website. Wikipedia and other general encyclopedias are not good sources for obtaining reliable firearms related critical dimensions and specifications. It is good practice to at least double check critical information. I think a lot of dimensional problems with cartridges have to do with incorrect/inaccurate measurement conversions. Even for professionals it is not easy to think in measurement systems one is not totally accustomed to.

Francis Flinch (talk) 11:13, 13 January 2008 (UTC)

Hi Francis, Yes I though you were in the US ! You seem to know the business quite well, also over there. --Michel Deby (talk) 17:02, 13 January 2008 (UTC)

9x25 Dillon constant changing

last time I was here I had it so "9x25 super auto" would go 9x25 Dillon which is its real name but I will change it to 10x25 Norma. —Preceding unsigned comment added by 76.84.18.214 (talk) 02:20, 4 January 2009 (UTC)

The 9x25mm Super Auto G is an Austrian pistol cartridge design and was C.I.P. registered on 17-05-1991. It is not the same cartridge as the 9x25mm Dillon. The 9x25mm Super Auto G is dimensionally somewhat different from the 9x25mm Dillon dimensions stated in the 9x25mm Dillon Wikipedia article. In the QuickLOAD internal ballistics software suite the C.I.P. 9x25mm Super Auto G and wildcat 9x25mm Dillon are listed as 2 different cartridges. The discussion at http://pistolsmith.com/viewtopic.php?t=28099 indicates both cartridges are necked down 9 mm variants of the 10 mm Auto, so it looks they are 2 executions of the same basic idea. The 9x25mm Dillon is up to now unknown by C.I.P. and can therefore impossibly be described in C.I.P. documentation.--Francis Flinch (talk) 18:16, 4 January 2009 (UTC)

References?

I was considering trying to help improve this entry by re-writing some paragraphs as was suggested by another commenter, but I ran into a problem when I noticed that there doesn't appear to be enough (any?) specific references to this subject outside of Wikipedia. The two references given don't seem to be very relevant.

I see where the C.I.P. organization lists a value they call "Delta L" on their TDCC cartridge dimension data, but I don't see any description of what it is or how to use it.

Does anyone have any legitimate external references to a description of the "Delta L Problem" that they can share? CaboverPete (talk) 08:55, 8 January 2013 (UTC)

Sadly the C.I.P. does not publish their complete rulings as a free online PDF file anymore. The list in the article is derived from the C.I.P. rulings as is the explanation regarding Delta L. As you saw the online TDCC datasheets only mention the amount of Delta L if present. I think it is wise that C.I.P. mentions discrepancies in length between their C.I.P. rulings and the voluntary SAAMI specifications for certain cartridges so travelers know they can experience diemnsional surprises abroad. You can look at http://www.triebel-guntools.de/produkte/patronenlagerlehren/lehren-fuer-buechsenpatronenlager/schulterlehren/?sword_list%5B0%5D=delta. Unlike this German webpage its English translation does not explain anything regarding Delta L. The Schulterlehre „Delta L“ shoulder gauge adds the correct amount of length to test if non C.I.P. conform cartridges (like US made cartridges) will function in a chamber. Logic dictates there will not be a large demand for such specialized shoulder gauges. Delta L becomes annoying when a C.I.P. conform minimal chamber gets mixed with a in other jurisdictions dimensionally perfectly correct cartridge that is slightly longer then the C.I.P. rulings foresaw. Of course a chamber can be appropriately reamed to the maximum C.I.P. specifications to function correctly with relatively long cartridges and Treibel saw a market for shpulder gauges to check if such a job is done correctly. When a customer buys ammunition in a C.I.P. memberstate that does not conform to the current C.I.P. rulings he can claim this if his chamber is C.I.P. conform. Abroad outside the C.I.P. zone the customer has to verify for himself if the ammunition he bought over tehere will work in his C.I.P. conform arm. If you can read German also see http://lutz-moeller-jagd.de/Waffen/Technik/Triebel-delta-L.pdf. In English see less legit sources like http://www.gunandgame.com/forums/powder-keg/46869-foreign-chamber-ammo-standards-delta-l-problem.html and http://www.milsurps.com/showthread.php?t=20107. The second C.I.P. source, sadly not online anymore, is a most relevant source since it is the legal source for Delta L.--Francis Flinch (talk) 11:53, 8 January 2013 (UTC)

Thanks for the info. I was thinking that, along with better references, another thing that would improve the article and provide a more clear explanation of the Delta L problem would be an example of how it is calculated. I'd like to see how the values for the .30-06 (0.16 mm), .257 Roberts (0.15 mm) and even the .243 Winchester (0.10 mm) are calculated.

I've had a look at the specs for each of those and it wasn't clear where the Delta L values came from. I don't have access to the CIP explanation of Delta L or CIP's description of the problem, so I'll need some help here. Thanks. CaboverPete (talk) 05:51, 9 January 2013 (UTC)

It might be less complex than you think. From C.I.P. (Dicisions 4.2, 5.2 III headspace 4):

A special procedure for checking the headspace is required in the case where the two conditions given below apply at the same time:

a. If a rimless calibre is involved where the "maximum" cartridge protrudes by an amount ΔL relative to the "minimum" chamber and

b. If this calibre is used in a type of weapon that is significantly affected by the condition described at an above (e.g. hinged bolt, breech block), then this situation must be sorted out by mutual agreement between the Proof House and the manufacturer.

If the two criteria given above should apply to the weapon in question then the headspace check must be done using a specific gauge for that calibre:

Minimum gauge (ΔL): when lengthened by an amount ΔL in comparison with a normal gauge, and then inserted into the chamber, the locking of the breech must be practicable.

Maximum gauge (ΔL): designed on the same basis as the minimum gauge (ΔL) taking into account the maximum headspace figures given in paragraph 5. (Paragraph 5 contains the lists and ΔL list mentioned in the article.)

The value of ΔL must be taken from the relevant calibres in the CIP TDCCs. [XXVIII-57]

There are some remarkable discrepancies in the TDDC/Dicisions lists you might not be aware of. In 2007 the 5.45 x 39 (a Russian service cartridge designed in the Soviet era) is listed with a ΔL of 0.16 mm, in the 2007 TDDC this is not mentioned. The 6.5 x 55 SE TDCC does also not mention any ΔL. There are more examples of that if you look into a that. If there is a ΔL present also varies with the year of a C.I.P. publication. This is an example that C.I.P. decisions are not static and the data in the COMPREHENSIVE EDITION OF ADOPTED C.I.P. DECISIONS document is subject to changes. C.I.P. does however state the TDCCs prevail in this regard and the current TDCCs are made available online.--Francis Flinch (talk) 10:04, 9 January 2013 (UTC)

According to this CIP passage, it's more of simply a design consideration especially for manufacturers of breech block and hinged bolt arms. I'm failing to see how this would be considered a problem. It seems that it only becomes a problem if such manufacturers of those specific arms don't take the specification into account.

This article on the Delta L Problem suggests that there is a problem largely due to an incompatibility or difference between the SAAMI specs and the CIP specs for the same cartridge, but looking at the specifications, that doesn't appear to be the case and there's no mention of that in this CIP passage. I'm wondering what that statement is based on.

Would it be a fair statement to say that SAAMI doesn't consider this Delta L dimension to be a problem? Even CIP doesn't seem to take it very seriously or refer to it as a problem. CaboverPete (talk) 16:26, 9 January 2013 (UTC)

It can be an annoying problem but it is normally no dangerous problem, so taking ΔL into account when designing/producing a chamber is wise. C.I.P. normally does not check headspace when proofing arms. They will do it if you order and pay for a headspace or dimensional check and I guess when their proofing rounds do not fit into a weapon to proof fire it. There are European made bolt action rifles with relatively tight chambers that have exhibited ΔL and annoyed the user. Normally changing the ammunition or carefully reaming the chamber solves this. The main reason for ΔL in case the chamber is not produced too small is differing ammunition standards or a total lack of standards since the world has much more jurisdictions than the relatively few C.I.P. and SAAMI states. For your information SAAMI and C.I.P. are in contact. The Director of the C.I.P. Permanent Bureau is responsible for maintaining relationships with SAAMI. Like you I never saw a SAAMI document mentioning ΔL at all. It must be a C.I.P. concept. Look at http://lutz-moeller-jagd.de/7,62-mm/30-06-5.htm#.30-06_delta-L. ΔL is discussed here in German and German hunters ask and wonder and get advice by a small German ammunition manufacturer about problems they experienced with .30-06 Springfield rifles. If you can not stand critical viewpoints regarding American engineering the page will contain some hard to digest text parts.--Francis Flinch (talk) 21:02, 9 January 2013 (UTC)

I'm afraid I really don't see what a lot of that has to do with the issues I mentioned. Once again, I'd like to specifically focus on the statement in this article where it says:

Conflicting industry standards

"The main cause for the [Delta L] is that [C.I.P. and SAAMI] have assigned different standards for the same cartridges. This leads to officially sanctioned conflicting differences between European and American ammunition dimensions and chamber dimensions."

I haven't seen any support for this statement. I'd like to see some specific examples of differences in cartridge dimensions of the sort that would result in the kinds of problems mentioned. What cartridge? Which dimension? So far, I haven't come across any when comparing dimensions of cartridges and chambers between the SAAMI and CIP specs. Do you know of any specific examples? If not, then doesn't this call into question the accuracy of that statement?

One other thing, if you look at the SAAMI spec for the .243 Winchester, for example, and read the headspace dimension for the cartridge (41.50 mm max.) and the headspace dimension for the chamber (41.40 min.), it seems to me that the spec. was intentionally designed so that at their dimensional limits, the cartridge would protrude by 0.10 mm. I'm sure it's no coincidence that the CIP spec shows a Delta L value of 0.10 mm.

Doesn't this mean that the Delta L amount was intentionally designed into the original spec.? Even though SAAMI doesn't identify or call it Delta L, it's still there, apparently, when the dimensions are analyzed. It's not caused by some difference in dimension spec between SAAMI and CIP. Correct?

Anyway, I hope we can focus on these two specific issues and come to some understanding or resolution.

BTW, I hope you realize that anecdotal stories about the experiences of annoyed users and such are only considered acceptable if there are adequate references. I'd certainly be interested in such, naturally, so if you have some references I'd appreciate them. They would make interesting reading. Thanks. CaboverPete (talk) 23:39, 9 January 2013 (UTC)

The statement must be incorrect and you can edit the article accordingly. I do not own the article and have no problem with improvement. Looking in C.I.P. and SAAMI datasheets will not help much. Intentional design appears improbable. Why would 21st century American ammunition like the 375 Ruger be intentionally designed with ΔL in mind, since SAAMI does not mention ΔL and will not help selling ammunition marketed for hunting large game. ΔL is a headspace issue but should not be mixed up with regular headspace. In the TDCCs you will see Fe (headspace) just above ΔL at Miscellaneous Dimensions. Fe is generally 0.10 or 0.15 mm for rimless rifle cartridges that headspace on the shoulder depending on the nature of the chambering. Equal amounts of ΔL and Fe as you saw or nearly equal amounts like for the 300 Rem. Ultra Mag. do occur but are coincidental. ΔL informs you that annoying surprises have to be taken into account for that particular chambering. Many firearm users in C.I.P. member states buy and use arms chambered for ΔL cartridges. Sometimes they know in advance they can be confronted with barely fitting cartridges (non fitting is much rarer) that need firmer operation of the locking mechanism and you will probably not hear them complaining. The complaining ones just can not blame a C.I.P. governed arms manufacturer for producing a chamber that did not take the maximum cartridge + additional ΔL length in account but is further C.I.P. conform. While not mentioned ΔL also provides a legal basis (C.I.P. rulings have the power of law for civilian use) to add ΔL to a chamber.--Francis Flinch (talk) 10:51, 10 January 2013 (UTC)

Before making any further changes to this article, I think the most important thing to do right now is try to establish the facts and make sure that they are verified from reliable sources. Don't you agree?

There's an obvious question that needs to be answered: Why were chamber headspace lengths for certain cartridges designed to be smaller than the maximum cartridge headspace lengths? Don't you think that question needs to be answered first before claiming that there is a problem?

Perhaps only someone involved in firearm development and design can answer that. In the mean time, there are some serious problems with this article, so I hope that gets sorted out soon. CaboverPete (talk) 20:15, 10 January 2013 (UTC)

The website of Mr. Möller is a website of such a designer, developer, producer and vendor. You can buy his products at http://lutz-moeller-gmbh.de/index.html. You probably thought the ΔL texts on his website were small talk. Möller likes to publish Q&A matters and arms related discussions with his customers online. Like any German based producer and vendor his products have to be conform to C.I.P. and other specific German rulings and the company has to obtain and keep additional licensing to produce and sell potentially hazardous firearms related products. German companies in this field are due to the imposed (professional) requirements and legal burdens generally not mom and dad operations. Producers have to deal with C.I.P. proofhouses on a regular basis and must be able to obtain various type permits (that can be tedious to obtain since testing procedures and costs are often involved) before potentially hazardous products like ammunition or firearms (parts) are deemed safe for end users by C.I.P. and/or other authorities and can be produced and commercially offered by them. German hunters with a reloading permit are for instance not allowed to reload ammunition for commercial purposes. In the US many fire arms users would laugh about such strict regulations and the paperwork that comes with it.--Francis Flinch (talk) 18:32, 11 January 2013 (UTC)

Are you planning to contact him to see if he can answer the question about headspace? CaboverPete (talk) 19:00, 11 January 2013 (UTC)

No, the discussions and his comments on http://lutz-moeller-jagd.de/7,62-mm/30-06-5.htm#.30-06_delta-L are clear enough to me and since customers complain and Möller tries to solve their problems with his ammunition (.30-06 Springfield is one of the main chamberings used by German hunters) must be legit. He even writes Delta-L-Fehler (= Delta-L-Fault). Keine maßgerechte .30-06 Patrone paßt mit dem zulässigen Verschlußabstand in maßgerechte .30-06 Lager. Das ist der delta-L-Fehler = Wahnsinn! Nur wenn die Patrone das Lager um 0,15 mm überragt, bietet das Lager der Patronenschulter hinreichend Platz. Ich meine, das ist Murks, wäre eines deutschen Ingenieures nicht würdig! My poor translation: No correctly sized .30-06 cartridge fits with the maximum allowed headspace in a dimensionally correct .30-06 chamber. This is delta-L-error madness! Only when the chamber protrudes 0.15 mm, the chamber provides adequate space for the cartridge shoulder. I think, this is nonsense, and would not be worthy for a German engineer.

I agree with Möller the Fe + ΔL concept is no example of fine engineering, but it works and is allowed. Möllers opinions regarding American engineers and cartridge design are his and not mine.--Francis Flinch (talk) 20:18, 11 January 2013 (UTC)

In an attempt to explain what I think of Mr Möller's ideas, let me begin with this:

One of the dimensions that determines the Delta L value is the minimum chamber headspace.

If the minimum chamber headspace dimension was removed from the specifications, what do you think firearm designers would change in their designs?

Please give this some thought and let me know what you think. CaboverPete (talk) 05:58, 12 January 2013 (UTC)

I took the liberty to start on the left margin again. What I think is that the Fe + ΔL concept is no example of fine or elegant engineering, but such an academic opinion is futile. By the way Fe is the maximum allowed amount of excess room for the headspace datum reference and every chambering has a Fe value assigned to it. Fe basically informs how much shorter a cartridge case can be before it becomes to short for its corresponding chamber. Fe has nothing to do with ΔL, which only few chamberings have. ΔL might be regarded as an example of the "In theory there is no difference between theory and practice. In practice there is." Yogi Berra wisdom. Fe + ΔL effectively pushes the maximum amount of excess room to headspace on further out. C.I.P. will not listen to the opinions of Mr. Möller, Wikipedia, you or me and I do not have the impression ΔL is high on the agenda of most citizens or politicians in C.I.P. member states either. I think keeping Fe relatively small to avoid excessive case stretching to reduce the chances of ruptures and uncontrolled gasflow in a high pressure system is sensible. Rimless rifle cartridges have generally high operating pressures and logically relative small Fe values. Fe values in pistol and revolver chamberings are higher even in high pressure chamberings that exhibit "rifle like pressures" (have a look at .500 S&W Magnum and its TDCC Fe). Adding ΔL to solve rare dimensional problems reduces safety margins somewhat, but it works in practice. Most ammunition is made somewhat under the maximum allowed dimensions anyhow to avoid dimensional problems and tested safe and C.I.P. conform before it gets an approval certificate for sale to end users. What C.I.P. decides and becomes law - elegant or not - we all have to live with and act accordingly to in C.I.P. member states.--Francis Flinch (talk) 10:04, 12 January 2013 (UTC)

Was that supposed to be an answer to the question I posed? I wasn't talking about anything to do with the Fe dimension.

The question is:

If the minimum chamber headspace dimension was removed from the specifications, what do you think firearm designers would change in their designs?

It doesn't require too much thought, really. Anyone with a basic understanding of firearm design and specifications can answer that easily. It's a very simple answer. And I think it's important for me that I know you understand it in order for us to continue having a productive discussion. Because, if you don't understand it, then it will be difficult or impossible for me to explain anything further.

If you would, please give the question some thought and try to answer that for me. I would be surprised if you would find it difficult. If you have trouble understanding the question, just let me know and I can give you some hints. And thank you for moving the margin. CaboverPete (talk) 14:29, 12 January 2013 (UTC)

Technically designers would probably like to start all over again on a worldwide basis and remove the excess materiel that would interfere with fitting every corresponding headstamped cartridge they can find. By doing so they would have to ponder how to deal with previously produced products and standards, how to handle unexpected future problems, circumvent related legal problems, and keep insured against professional liability. We are not (re)designing chambers, changing problematic C.I.P. rulings or improving international fire arms safety or fine functioning here, so continuing this discussion might be fun but is futile and will not produce better referencing.--Francis Flinch (talk) 20:08, 12 January 2013 (UTC)

No, sorry, that is not correct. The answer is much simpler and somewhat the opposite of what you just said. Please continue to try to discover the answer. I'm now very anxious to share with you what I know about the topic so I hope you won't keep me waiting. I promise that you will be very happy to know the solution. CaboverPete (talk) 20:55, 12 January 2013 (UTC)