Bullet seating depth for 7.62 x 51mm MK 319 MOD 0

Federal T762TNB1 = 7.62 x 51mm Ball, Rifle, Barrier MK 319 MOD 0; 130 grain OTM (or at least it is advertised that way). This is a non-NATO cartridge.

This box contained rounds headstamped “ F C 1 2 “ and “ F C 1 3 ” , with the FC at the 12:00 position and the two digit date at the 6:00 position.

Below is an example of a cartridge from the box, the bullet is seated in the cartridge so that the bottom ring on the 130 gr OTM bullet is exposed. Overall cartridge length is 71mm which approximates the length of a 7.62 x 51mm NATO ball cartridge.

Most images of this round found on the web seem to be based on the image provided by ATK (Federal) circa 2009, shown below, which show the bullet seated to the top ring of the 130 gr OTM bullet.

So my questions are:

Is the cartridge from the box, pictured above, correct for bullet seating depth?
Is the cartridge shown in the photo below actually a “stock” photo of a standard 7.62 x 51mm ball round?
If the cartridge below actually is the MK 319 MOD 0 cartridge why the difference in the bullet seating depth between the cartridge shown above and the one pictured below?
The description of the round in the picture bellow uses the term “Carbine” while later descriptions of the round use the term “Rifle” is there a reason for a change in descriptive terminology?

Thanks in advance for any feedback.


Brian, this seating depth is correct for a Mk 319 Mod 0 cartridge as shown in pictures published as early as 2009, although the earliest headstamp I have seen so far is “F C 10”. The designation “Carbine” is not correct for this cartridge and it was likely confused with that of the 5.56 mm Mk 318 Mod 0 when the NAVSEA presentation* was created (May, 2009). Also, it seems that this cartridge image is unique to this presentation, so I guess that it could be an early development round.

The image below showing the current cartridge was published on June 1, 2009:

A sectioned bullet also shows some differences:



Edit: *The same picture and “Carbine” designation is also found in another presentation published by ATK in 2010.


Thank you for your explanation and information, very helpful. Yes the photo with the “Carbine” designation is from the 2009 NAVSEA presentation.


Should be this one:
lem.nioa.com.au/products/downloa … ements.pdf

ATK itself was not doing better in 2010:
lem.nioa.com.au/products/downloa … tional.pdf


Thanks for listing the web links. I did not have the second one on file.


While we’re discussing the MK319 Mod 0, does anyone have any information on this box? If the cartridges are loaded to the same specifications as the Mk319 Mod 0, why give the bullet weight as 125gr? Unlike other Mk319 Mod 0 rounds I’ve seen that do not have the NATO (+), the cases from this box are headstamped (+) LC 10 and (+) LC 11. Other than this, the cartridges are indistinguishable from those shown in this thread. Despite the box label, the bullets are 130gr. Powder appearance and charge are very close to a legit Mk319 mod 0. There is no lot number on the outside of the box, just 124311 stamped on the inside flap.


Hi Dave, it was made by Bitterroot Valley Ammunition & Components (BVAC) also exists in 5.56MM Mk 318 Mod 0. Regards, Fede.

As a matter of interest, NATO specifications for 7.62 x 51 ammunition include minimum and maximum bullet weights of 8.4 g (130 grains) and 10.0 g (154 grains) respectively.

That does not of course mean that NATO armies can’t use ammo with bullets outside this range (M118LR sniper round, for instance), but as far as I know such ammo is used for special purposes only, not for general use in MGs etc.

The NATO mark (+) on a case is intended to identify this cartridge as manufactured in accordance with a Standardization Agreement, which for the 7.62x51 is STANAG 2310.
NATO considers deforming bullets like Mk319 as illegal (see “Training in the Law of Armed Conflict” Standard on the public NATO website). Strictly speaking, (+) should not be used on Mk319, M118LR and similar 7.62x51 cartridges, because they deviate from STANAG 2310.

I’ve been searching through that website but they have hidden the article very well - can you provide a link please?

One thing to note about the cartridges produced by Bitterroot Valley Ammunition & Components (BVAC), they reload fired cases in the production of ammunition. That’s why the cases from NATODave’s box shown above have the " ⨁ " symbol.

MK 319 MOD 0 cartridges from the Federal box shown at the beginning of the thread have a military style headstamp without the " ⨁ " symbol:

Tony, on website www.nato.int move the cursor over E-LIBRARY and in the menu that opens click on STANAGs. (No premature cheers, there are no really interesting STANAGs available on that page.)
A download list of 178 items opens. Item 174 is what you are looking for. Click on the document marked as ATrainP-2.

Let your PDF reader go to page 106 of the PDF document (paper page F-78). There you find the statement I refered to.

Got it, many thanks!

The NATO (+) has no official significance. It is generally accepted that any cartridge manufactured by a NATO country that bears the (+) will chamber correctly, but it should not be assumed that it will produce the expected level of performance or safety. Ammunition manufactured by non-NATO countries that bear the (+) cannot be assumed to meet any specification or standard.

The NATO symbol of interchangability has more meaning than the (+). It is the only symbol that ensures that the ammunition can be exchanged on the battlefield.