7.62mm MK319 SOST

A couple of years ago the development of the 7.62mm MK319 was announced, essentially a 5.56mm MK318 SOST scaled up to the larger calibre. Initially this used a 130 grain bullet, but I have a distinct recollection of having heard at a briefing (probably NDIA 2010) that the users thought this was a bit light so they were looking at a 155 grain version instead.

Does anyone know any more about this? Is the MK319 in service, if so is the weight still 130 grains or has it been increased?

Can’t speak to “in service”, but it’s definitely in production by ATK and the bullet weight on what I’ve seen is 130gr (OTM, same as the 5.56 product).

Rejected lots have been on aftermarket net sales for a few months; www.kiesler.com has both the 5.56 and 7.62 ‘Barrier Blind’ for sale.

I had a little writeup about the Mk319 in IAAJ a few issues back. I’ve not heard anything about a lighter bullet or combat use. I don’t understand the warning about “CANNOT be used in civilian weapons chambered for .308 Winchester due to difference in the .308 Winchester and 7.62mm NATO chambers.” as those chamber differences are inconsequential.

Cartridge, Caliber 7.62mm Ball, Rifle, Barrier
MK 319 MOD 0
NSN: 1305-01-572-8492


The MK 319 MOD 0 7.62mm cartridge is designed for combat use in the MK 17 SCAR-H and all magazine fed legacy weapon systems chambered for the 7.62mm cartridge. The MK 319 MOD 0 cartridge is designed to provide the following:

• Enhanced performance in carbine length barrels
• Enhanced, consistent accuracy – NTE 2.25 MOA @ 600 yd
• Enhanced Intermediate Barrier defeat capability (Auto glass, doors)
• Enhanced behind barrier terminal performance
• Enhanced CQC soft target terminal performance
• Temperature stable and flash reduced propellant

The projectile weight is 130 grain. This round is NOT a NATO standard round and it CANNOT be used in civilian weapons chambered for .308 Winchester due to difference in the .308 Winchester and 7.62mm NATO chambers. These cartridges are intended for use in magazine fed weapon systems only. Initial production quantities will be packaged in 20 round cartons, 23 cartons per M2A1, 920 rounds per wirebound box. A stripper clip/bandoleer pack will be provided in the near future. Any new pack will have a different NSN. Current cost is $0.78 per round ($717.60 per wirebound). As a point of reference, M880 ball ammunition is approximately $0.90 a round.


Milestone Decision Authority: PEO-SOF Warrior, United States Special Operations Command, MacDill AFG, FL

Program Management Office: Program Manager, Joint Special Operations Program (JSOP), Branch Manager Small Arms Ammunition and Testing Branch (SAATB) Code JXNN, Naval Surface Warfare Center, Crane IN

Authorization/Validation: USSOCOM Joint Operational Requirements Document (JORD) For SOF Combat Assault Rifle (SCAR) System, ACAT III, Revision 3 dated 28 March 2007.

System Mission: Specifically developed for combat use in the MK 17 SCAR-H, and all magazine fed 7.62mm legacy weapon systems.


Manufacturer: Federal Cartridge Company

Caliber: 7.62mm x 51mm

Instrumental Velocity: 2,920 feet per second (ft/sec) plus or minus (+/-) 30 ft/sec
@ 78 feet from the muzzle of a standard 22" 7.62mm Small Caliber Ammunition Test Procedure (SCATP) test barrel.

Chamber Pressure: The average chamber pressure of the sample cartridges, conditioned at 70 degrees plus or minus 5 degrees F, shall not exceed 60,000 psi.

Max. Effective Range: 600 yards (550 meters)

Maximum Range: 4,482 yards (4,098 meters) @ 30 deg. elevation

Bullet Weight: 130 grains, BC = .277

LAT Accuracy Req.: The extreme spread of any individual ten-shot (10-shot) group shall not exceed 6.0 inches at 200 yards. The average extreme spread of all ten 10-shot groups shall not exceed 4.75 inches at 200 yards.

Manuals: P/JXNN/C08/1606 Specialized Storage And Maintenance
Procedures, USSOCOM Peculiar Small Arms Ammunition

Not lighter, Dennis, but heavier - 155 grains.

I have just been told by a good source that Crane are working up a 155 grain version of the MK319, so I wasn’t wrong - just a bit ahead of myself!

Further correction - Crane were working on this (it would have been a bit longer with a boat-tail) but it failed to obtain funding.