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The 308 Winchester and 7.62X51 are identical cartridgesThe cartridege was developed in the USA as a commercial round with an Imperial measurement ie .308 inches. The cartridge was adopted in Europe where all military calibers- even in the UK who still use miles instead of kilometres- all calibers are metric hence 7.62x51 millimetres. What differs and confuses people is that headspace 'field' gauges for military weapons are normally more lenient than 'field' for commercial rifles. Obviously a cartridge case having been fired in a military rifle on the limit of the military 'field' gauge can never be chambered in a commercial rifle unless it is full resized.

Just to confuse the issue- my 'military' FN FAL semi automatic rifle is stamped 'cal 308' as it was sold in Rhodesia in the 70's as a 'sporting' weapon whereas my Musgrave single shot Bisley competition rifle is stamped 'Cal 7.62'The Musgrave competition '7.62' has all chamber dimensions on minimum and will not chamber any round fired in another 7.62/308 (without full sizing the case)whilst the semi auto '308' has 'field' dimensions and will chamber just about any fired 308/7.62

Brian41.244.122.31 15:21, 24 July 2007 (UTC)[reply]

The .308 Winchester and the 7.62 NATO (7.62 x 51) are not identical, the former is very slightly larger. However, they are sufficiently similar that 7.62 NATO ammunition can be safely fired in .308 Winchester rifles and vice versa. 86.166.66.41 (talk) 15:12, 7 February 2011 (UTC)[reply]

I noted that this article says the dimensions for 7.62 x 51 are different than the .308 Winchester. Also, there are separate articles for each of these rounds, that maybe should be merged into one article, since they are really variants. Regarding the dimensional difference, the referenced link on the 7.62 x 51 mm NATO article goes to a source that does seem to be authoritative. Can someone try to check this out and post a reliable source for the stated dimensional difference? I've only found some sources that wouldn't pass WP:RS that seem to say older military rifles may have a slightly difference headspace. To save time, here are the sources I have checked:

• SAME The Handloader's Manual of Cartridge Conversions, Book by John J. Donnelly, Stoeger Publishing, 1987, ISBN 978-0883172698 p. 356
• SAME Handbook for Shooters & Reloaders vol I, Book by P.O. Ackley; Plaza Publishing, 1962, ISBN 978-9992948811 p. 420
• SAME Designing and Forming Custom Cartridges, Book by Ken Howell, Precision Shooting, 1995, ISBN 0-9643623-0-9 p. 228
• SAME Hornady Handbook of Cartridge Reloading vol I, Sixth Edition; Book by Hornady Mfg Co, 2003 pp 384,391
• SAME * Accurate Smokeless Powders Loading Guide Number Two (Revised), Book by Accurate Arms Co, Wolfe Publishing, 2000 p. 260

Note that for those who don't have access to them, the 2nd and 3rd references are books devoted almost exclusively to cartridge drawings and dimensions. Probably we need someone who has a more military focused reference manual, I suspect that's what's missing. Or perhaps it's just tolerances - see http://www.armalite.com/images/Tech%20Notes%5CTech%20Note%2011,%20Headspace%20020328.pdf Thanks in advance. Arthurrh 21:44, 14 July 2007 (UTC)[reply]

.308 Winchester and 7.62x51mm NATO
Case Specifications

	.308 Winchester	C.I.P. max. dimensions	7.62x51mm NATO	Difference . 308 Win./7.62 NATO
Bullet Dia.	0.308"	0.308"	0.308"	0
Neck Dia.	0.344"	0.343"	0.338"	0.006"
Shoulder Dia.	0.454"	0.454"	0.447"	0.007"
Base Dia.	0.470"	0.471"	0.466"	0.004"
Rim Dia.	0.470"	0.473"	0.470"	0
Rim Thck.	0.049"	0.067	NA	NA
Case Length	2.015"	2.015"	2.018"	0.003"
Cartridge Length	2.75"	2.80"	2.75"	0

The following table was generated from data referenced in the book Cartridges of the World, 9th Edition by Frank C. Barnes (Edited by M.L. McPherson), Krause Publications, 2000, ISBN 0-87341-909-X p.90 (.308 Winchester) and p.345 (7.62x51mm NATO) and the 2007 C.I.P. TDCC.

This is the reference point I was referring to when I wrote the statement "The 7.62 × 51 mm is smaller by a few thousandths of an inch in some dimensions". I will note it in the article. I'm currently attempting to locate the NATO specifications for 7.62x51mm to see what they have to say regarding case measurements and how those relate to SAAMI specs for .308 Winchester. It is entirely possible that the data from my source is simply incorrect, though I do consider the source authoritative.

I don't think there can be much argument when it comes to chambering specs. They're very widely reported to be different.

Raygun 09:05, 18 August 2007 (UTC)[reply]

Excellent work! Also note that what you've come up with shows 7.62 NATO to be smaller than .308, which matches what I've heard: 7.62 NATO in .308 chambers is "OK", the reverse can be an issue. Hga 09:47, 18 August 2007 (UTC)[reply]

Thanks for the info. I added a C.I.P. cartridge drawing and provided a link to the C.I.P. TDCC rulings on the .308 Winchester in the article. Now there are 3 dimensions sets. It seems the UK MOD and NATO use the C.I.P. proofing pressure standard for this cartridge. This does not rule out that the 7.62 NATO dimensions differ from the C.I.P. .308 Winchester dimensions. To avoid problems it is normal that factory cartridges produced in C.I.P. countries are slightly smaller dimensioned than the here quoted maximum by C.I.P. allowed dimensions. Francis Flinch (talk) 18:52, 19 February 2008 (UTC)[reply]

Why are the Cartridge dimensions in metric? This Cartridge was designed by a US company long before metric was ever used in the USA. The USA still has not adopted the metric system. The Cartridge dimensions diagram is confusing to Americans. Since the Cartridge was designed by an American company, by Americans, for Americans - the dimensions should be in inches, not metric. —Preceding unsigned comment added by 168.39.183.58 (talk) 16:01, 29 February 2008 (UTC)[reply]

It probably has something to do with the fact that the United States is one of only three countries world-wide who have not at least partially adopted the metric system. The .308 in the form of the 7.62x51mm NATO is widely deployed, and as such it only makes sense that the measurements are in metric. I do, however, wish there was an alternative Image, or a version with both. Scott Paeth (talk) 07:27, 10 June 2008 (UTC)[reply]

Done. Imperial measurements added. CaboverPete (talk) 18:39, 27 February 2010 (UTC)[reply]

Simple - it's a NATO standard cartridge, and NATO uses the metric system. And the metric system shouldn't be confusing to any American born in the last 50 years, we all learned it in school. --71.104.18.213 (talk) 17:19, 6 September 2008 (UTC)[reply]

The point of the discussion is that the .308Win and 7.62NATO are somehow different. In fact, they are, since there are two standards involved -- one driving the .308 and another specifying the 7.62 parameters. These two standards use different scales for dimensions and different ways of measuring pressure. Also, as noted in earlier discussion, research into cartridge dimensions in some sources show actual differences in cartridge dimensions. These could be caused by rounding errors in dimension translation from Imperial to Metric or vice versa. It would seem appropriate for an encyclopaedic resource to present the raw data and not interpretation. Therefore, presentation of the parameters in the same scale as the specification would seem to be primary, with translation of those parameters into a more readily understood or comparative scale taking the secondary or parenthetical position. That said, I do not know of any 7.62NATO cartridges that are not manufactured within SAAMI .308Win external dimensions, nor are there are .308 cartridges being manufactured which do not meet NATO external dimensions. The SAAMI minimum chamber headspace is 1.6300 inches, and all current cartridge manufacturers (7.62NATO and .308Win) hold under that dimension. (The NATO minimum headspace is 1.6355".) However, the internal capacity of the case is different, because a dimension not listed above (the web thickness) is heavier in NATO cartridges, resulting in lower case capacity in the 7.62NATO. This difference can be seen when weighing the empty cases: a .308Win typically weighs 150-160gr and NATO brass weighs 190+gr. According to field measurement, a typical commercial .308Win yields 55,000 psi and a typical 7.62NATO 60,000 psi in the same rifle. (SAAMI would allow ~62000 psi max for the .308Win.) The 7.62NATO's smaller case capacity provides a demonstrably higher pressure, and needs to be taken into account by reloaders. This web thickness leads us to the real difference between 7.62NATO and .308Win, which is not so much in the external case dimensions, but the intended application. A NATO chamber is built with a larger headspace than a .308Win chamber on purpose. The headspace gauges are not different because of some rounding, or military "intelligence," but NATO chose to extend the headspace beyond what the .308Win chamber found acceptable. The .308Win rifle must have a headspace under 1.638" (the Field Reject dimension). Any headspace longer than this is unsafe for .308Win ammunition (having a thinner web). A NATO rifle may have a headspace up to 1.6455" (Field, again). This means that a NATO rifle with a headspace of 1.642" can safely fire 7.62NATO ammunition (with the heavier brass), but should not be used with .308Win ammunition. Because of this difference, there must be a distinction between NATO and commercial ammunition, and therefore two Wiki entries, each holding close to the specifications that define it (including the scale). kc (talk) 23:04, 31 December 2009 (UTC)[reply]

Maybe one of the usual editors could find this article by Ray Meketa helpful in detailing the history of development of the .308 Win from the .300 Savage. History: .30-80 WCF - The Origin of the .308 Winchester Regards. Trilobitealive (talk) 02:55, 22 August 2015 (UTC)[reply]

There have been a number of editing mistakes on the infobox which are apparently due to failure (of multiple editors including myself) to adhere to the specific guidelines from Template:Infobox firearm cartridge regarding data entry. See my most recent edit to the present article to see the result of the most recent attempt to fix it. This resulted in the entry of the correct data for all 6 cartridge weights, but the template then deleted showing the last one. The template only allows 5 weights! I will leave it to the editors to decide which of the 6 must be removed. If I have a vote it would be to remove the 165 or 168 since these weights are nearly the same. Unless some genius knows how to modify the template to accept 6 weights.Trilobitealive (talk) 16:12, 3 October 2015 (UTC)[reply]

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I check pages listed in Category:Pages with incorrect ref formatting to try to fix reference errors. One of the things I do is look for content for orphaned references in wikilinked articles. I have found content for some of .308 Winchester's orphans, the problem is that I found more than one version. I can't determine which (if any) is correct for this article, so I am asking for a sentient editor to look it over and copy the correct ref content into this article.

Reference named "NRA High Power":

• From International Confederation of Fullbore Rifle Associations: "NRA High Power Rifle Rules, Revised January 2014, p. 67-70" (PDF).
• From Long range shooting: NRA High Power Rifle Rules, Revised January 2014, p. 67-70

I apologize if any of the above are effectively identical; I am just a simple computer program, so I can't determine whether minor differences are significant or not. AnomieBOT⚡ 04:25, 18 December 2017 (UTC)[reply]

The unit or designation of measure is Caliber. Caliber is a unit "based" on inches and/or millimeter (mm). When using the designation of caliber it is not represented directly as a measurement of inches. Refer to the definition of caliber. Caliber is expressed in hundredths or thousands of an inch depending on the number of digits. When referring to cartridges, bullets or chambers the units or designation used is caliber. This would be expressed without any leading decimal. Example: 22 LR is the 22 caliber Long Rifle cartridge. It may be approximately 0.22 inches in diameter; however, the Caliber is 22.

Leaving the decimal out of imperial specifications is intentional. It is not common language to say "Point 22 LR" or "Dot 22 LR", the common phrase is "Twenty Two LR". It is also easy to miss read or not see markings with a leading dot, thus another reason the unit of caliber is used.

This page is for specifications in caliber, This is what is used in the industry. Expressing it incorrectly as for example .45 caliber would translate a measurement in inches of 0.45/100 equaling 0.0045 inches. Another example .223 Rem. If this is a caliber unit it would translate to 0.223 thousandths (0.223/1000), which would equate to 0.000223 inches. for empirical units caliber designation never has a decimal place. Metric calibers are also often but not exclusively written and used without a decimal (i.e. Caliber 762).

The title of these pages should be updated as well as the content to avoid confusion for people learning or understanding the correct terms.

Further information on the correct way to specify values and units. Values and the units used are separated by a space. Example 7 mm is correct, 7mm is not correct. Correct case of letters (upper, lower) is also important, mm = millimeters, MM who knows that that would be. Another example (5.56 x 45 mm). Both 5.46 and 45 are in mm (millimeters), note the spacing around the x and between the number (value) and the units (mm).

216.160.0.104 (talk) 21:09, 2 May 2022 (UTC)Scimernet[reply]

This article was the subject of a Wiki Education Foundation-supported course assignment, between 22 August 2022 and 9 December 2022. Further details are available on the course page. Student editor(s): Tbone 427 (article contribs).

— Assignment last updated by Tbone 427 (talk) 19:58, 20 October 2022 (UTC)[reply]