7.62mm NATO reference cases


Here’s a great box of 7.62 mm NATO ‘reference’ cases that I recently received in a trade with an unnamed retired swabbie residing in Arizona.

Does anyone know what purpose these served. There was a limited discussion on the forum some time ago regarding loaded reference cartridges, but what specifically were these empty primed cases used as a reference for?

Also, it seems to me that the ‘No waterproofing at mouth’ at the top of the label is not really needed; isn’t the waterproofing applied once a cartridge is loaded with a bullet. Why would anyone expect an empty primed case to have a waterproofed mouth?

That Arizona swabbie pointed out that the box these are in is a .45 ACP box - how resourceful that gang at the Frankford Arsenal was.


In the book “.30-06”, Chris Punnett describes primed .30-06 reference cases from Frankford Arsenal with a box label that is similar to your 7.62 NATO box. He indicates that they were made to very high tolerances and were used “to calibrate test equipment and gauges” and “to verify processes and instruments.” This info appears on page 213 if you have the book.


“NO WATRPROOFING AT MOUTH” probably refers to the black tar seal that alot of military rifle rounds use, which is applied tot he inside of the case neck before the bullet is seated.


Thanks twoaz for pointing out the reference in Chris Punnett’s book. I don’t know why I have these books if I don’t think to look in them. Unfortunately, “to calibrate test equipment and gauges” and “to verify processes and instruments” doesn’t say much regarding specifically how the reference cases were used. I imagine the person running the equipment could make comparisons between the reference case dimensions and capacity, and those of the cases coming off the line. I suppose it would be helpful if I knew more about the equipment and processes used in making center fire cartridge cases.

I would think that the tar-like sealant would not be applied to the inside of the case mouth until immediately prior to seating the bullet, so again, why would anyone expect a box of primed, empty cases to have been waterproofed. The 1945 box of FA .30-06 cases shown in Chris Punnett’s book also had ‘No waterproofing at mouth’ on the label.


Here’s a box from my collection

on the back the label is stamped: SMUFA Label 148, 14 Jun 65

The cartridges are headstamped:
12 O’clock NATO symbol
6 O’clock F A 65

The story that came with the box was that the dutch used these cartridges as reference while
testing others for adoption within the dutch army.



FlyingDutchman-- believe your M80 Reference cartridges are used for a different purpose than the Empty Reference Cartridges being discussed. The loaded Reference rounds are used primarily for setting up Pressure Test Guns. The cartridges come with a chart showing what the chamber pressure should be at various Temperatures and Air Pressures at the firing site.


Sometime back I opened a box of the 7.62mm Reference cases and gave them the Benchrest test. I weighed each one on an accurate scale. I cannot put my hands on the notes I took but I remember that they were very uniform in weight, rivaling some Benchrest cases. Uniformity in weight generally means uniformity in capacity which translates to consistent wall and web thickness. Very high quality brass. And that’s no joke.



These were used as a reference standard or benchmark


Reference cartridges are also used to test firearms for functioning, eliminating the possibility (probability?) of the
ammunition being a source of malfunctioning. I can’t say if, by regulation or whatever you would call the original state purpose for the rounds that this was one of the intended uses, but it is a use that they have been put to.
I would think that there were other uses for controlled-manufacture ammunition, reference, ballistic standard, or by whatever name, as well.

John Moss


Regarding the lack of a seal, which actually was answered briefly but accurately, I received the following interesting
information from Col. Hackley. It is more an answer or addition to Guy’s entry than anything I wrote, but I quote it
simply because it pertained to the this thread, and everything Col. Hackley has ever written to me was interesting and informative, as is this:

 "John:  The normal production method used at FA and the COCO plants was to apply the case mouth sealant

during priming which is still the case today at LCAAP. In yesteryear, the asphalt of lacquer-based sealant would not dry for about 72 hours depending upon the temp/humidity. So, you were committed to load the cases during that
period. Today water-based sealants are used and the drying time and delay to load is reduced. Calibration primer cases are primarily used for QC and malfunction investigation and are often provided to plants and contractors for
their loading and internal use. The cartons are marked “No waterproofing at Mouth” or “Without Mouth Waterproofing” because the cases may not be used for years and the waterproofing sealand would have dried and not serve its purpose. In addition, this allowed the user to either apply fresh mouth sealant or not as the test sample was being loaded for testing."

Regarding his answer, the part about “malfunction investigation” which I originally learned in discussion with friends from the Ordnance Company, U.S. Army Alaska, Ladd AFB, Alaska, during my tour there (I was in the Signal Company, but I was actually a personnel specialist at Command Headquarters and served the Ordnance Company and several other units, including my own, in that capacity), is what I alluded to about removing ammunition as the potential cause for weapon malfunction. At the time, on a tour of the shop, I probably saw some ammunition boxes marked “Reference” and didn’t know what in heck they were, and asked. I don’t recall - too long ago, but I remember learning about it, and many, many other things, from those guys. I didn’t collect cartridges in those days, but already was a gun collector and have been a shooter since before high school.

John Moss


Here’s the purpose of the Reference cartridge according to NATO:


6.1 Use of the Reference Cartridge.

A reference cartridge shall be used to establish range and equipment corrections in qualification approval, production and surveillance tests. In addition, the cartridges may be used to determine barrel serviceability or as a check on other equipment or ballistic measurements.

6.2 Responsibility

The North American Regional Test Center (ARRADCOM, Dover, N. J. 07801) in the United States will supply Cartridge Reference, NATO, 7.62mm (Drawing No. 20). The Regional Test Center in the United States will fire an assessment and publish the following values for the reference cartridge… [/i](here comes a list of the said values).

(from Document AC/225 (Panel III-SP.1) D/150, revised 1981, Nato Army Armaments Group, Infantry Weapons Panel, Sub-Panel on Nato Standard Small Arms Ammunition, Manual of proof and inspection procedures for Nato 7.62mm ammunition)




Schneider - pretty wide range. I think the operative phrase regarding uses other than calibration is
"…or as a check on other equipment." That allows a wide range of interpretation of its uses.

John Moss


Again, while this entire thread has been interesting, I have to point out that we are mixing discussions of two entirely different things thoughout the thread.

  1. Empty Reference Case–NOT the same as Reference Cartridges and used for quite different things.

  2. Reference Cartridges–Not the same as 1 above.


I think you’re splitting hairs. No, reference ammo and reference cases aren’t necessarily used for the same things.
Sometimes they are loaded with special loads for specific problem solving or calibration purposes. However, the subjects are TOTALLY related, and one leads to the discussion of the other. JMHO. Don’t mean to start a 20 or 30 entry argument.

John Moss


[quote=“RonMerchant”]Again, while this entire thread has been interesting, I have to point out that we are mixing discussions of two entirely different things thoughout the thread.

  1. Empty Reference Case–NOT the same as Reference Cartridges and used for quite different things.

  2. Reference Cartridges–Not the same as 1 above.[/quote]

I think I can see your point. Reference cases are made to exact Nato specifications, to be loaded elsewhere. Reference cartridges cannot be the same because there’s no exact specification for the loaded cartridge; I mean variations in bullet weight and materials and propellant weight are allowed.

Now I recall having seen ammo boxes marked “calibration components”. I don’t remember what the caliber was, or even if they contained loaded cartridges. Were these Reference too?


Schneider - I have two such boxes for "50 Primed Cases, Caltritridge Cal. .45, Calibration Components."
One is Lot FA-Y-45-251, Exp. Order 3365Ml, dated July 21, 1948. They are NPE Steel .45 cases headstamped
F A 47. The other is Lot Number FA &45-318, Job Order SST-R-1-293, dated 9 May 1951. It has the added
label markings of “Primer No. 27” and “No Waterproofing.” This box has Steel case NPE with headstamp “F A 51”.

I also have a full box of ball ammunition, Lot WCC-1-30-1 (the first “1” is overstamped with a black “ball” probably meant to obliterate it) marked “REFERENCE.” The ammunition is identical in appearance to ordinary ball ammunition
from Olin in the same era, and is headstamped “W C C 7 0.” Out of the box, it would lose all identity as any kind
of special load.

I do not know if, in the eyes of the U.S. Ordnance Corps, the Calibration Components are the safe as Reference Components, or not. Certainly the purpose would be somewhat similar, if not identical, I would think.

John Moss


Thanks for taking the time to ask Col Hackley about these cases and share his answers to both of the questions I originally raised about these cases.