ATK Special Operations “SOST” 5.56mm and 7.62mm Ammunition

The new SOST round from Federal Cartridge was engineered for the United States Marine Corps as a supplemental/replacement round to M855 green tip with more desirable terminal characteristics. NSN # 1305-01-573-2229, designated as the MK318 MOD-0, this round was designed as a “barrier blind” round and has superior penetration and better ballistic stability when shooting through glass, car doors, and other barriers where lesser rounds might be deflected. It was engineered after the Marine Corp identified barrier penetration issues with the M855 round. This new round utilizes a 62 grain open tip boat tail hollow point bullet with a lead core and reverse drawn copper jacket that creates an open tip.

From the press release from ATK:

MINNEAPOLIS, MN — Alliant Techsystems (ATK) announced today that it has received a $49 million contract from the U.S. Navy to produce a new special operations ammunition round with improved accuracy, stronger barrier penetration, and a lower muzzle-flash. ATK Security and Sporting developed the round in partnership with the Naval Surface Warfare Center – Crane Division under the Special Operations Science and Technology (SOST) ammunition program.

The SOST ammunition will be manufactured in 5.56x45mm and 7.62x51mm calibers, and is short-barrel optimized. It is designed for use with the MK16 and MK17 Special Operations Combat Assault Rifle Weapon System. Production will be performed at ATK’s Federal Premium Ammunition plant in Anoka, MN. Deliveries are expected to be completed in 2015.

“ATK is the clear leader in developing new ammunition technologies for commercial use,” said Ron Johnson, President of ATK’s Security and Sporting group. “We are now applying our research and development capability to satisfy the needs of our special operation forces.”

The new SOST 5.56mm and 7.62mm ammunition adds to ATK’s portfolio of specialized ammunition, including long-range products for both law enforcement and military applications.

ATK is an aerospace, defense, and commercial products company with operations in 24 states, Puerto Rico, and internationally, and revenues of approximately $4.8 billion. News and information can be found on the Internet at

Click here to purchase 5.56mm SOST ammunition.

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Comments (6)

  1. Not sure how that happened. When I leave,I take it off and lay it between the seat next to me with a pair of driving gloves concealing.(I don’t have my ccl yet, so that’s how I have to do it.} Point is, if anyone bum-rushed me and/or was fireing at me,my little jacketed hollow cavity Winchesters in .38 Spec. might better be supplemented by keeping a 6″ Mod 28 Highway Patrolman S&W 357 w/magnum FMJ rounds just for when you’re belted in, consentrating on vehicle control,and vulnerable. What little cover the windshield post or door may provide you as you sit there belted in, is more than offset by being in your way for defensive fire, if you have a 2″ Colt w/.38 Spec. JHC loads. even the windshield and door/body metal….I think that’s a fair comparison. some day I want to own an M1-A SOCOM. Maybe that’ll help make up for the fact that after all these years I never had a .308. But, now you got me thinkin’ ’bout diggin’ out my 788 in .223 and squeezin’ off a few……

  2. Now, I’ve been a hunter for 30 years so all this Zombie killin’ assault, para military stuff is new to me, or maybe I’m new to it, but I can say from a hunter’s pov both are excellent cartriges on so many levels. I’ve never owned a .308, and I consider that my loss, but even if I had and could go on and on about it, you wouldn’t have to take my word for it,just look at the poularity of both calibers in gun and ammo sales, and the pasionate posts of guys herolding their favorite guns,loads, and ballistics in forum blogs. I do have a remington 788 in .223 Rem. with a heavy 24″ bbl., and I really enjoy it with the various factory loads hunting and informal target/plinking. Both my son and I have taken deer with it……..but under desirable conditions and with good shot placement. If you go back up to the first paragraph where it talks about “BARRIOR BLIND”,describing the round as being able to have some amount of semi-hard target capability, at least in as much as possiblly having to fire thru a car door or windshield, that sort of thing. They’re talking about developing each of these calibers for this, it would seem logical to me that the .308 would be ideally suited and hard to beat. Barrier Blind is actually something I’ve recently been considering in a vehicle, but with a handgun. I wear a Colt Agent open carry daily on my 5 acres, and when I leave I

  3. Stop with the 5.56 already. Go with the .308 or something. I have hit many a bad guy with the 5.56 and then had to hit them again.

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