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Guns & Ammo Magazine said:
When a six-man Special Operations team looking for Scuds in Iraq in early 2003 ran into a reinforced Iraqi infantry company, the future looked grim for the Americans. Facing overwhelming odds, it was quickly decided that three men armed with sniper rifles would cover a hasty retreat back to the LZ. With these odds death, or worse, seemed certain.

Yet the ensuing firefight did not go as the Iraqis had planned. Rather than being overwhelmed, the three American Snipers instead put down a hail of highly accurate rifle fire. Advancing against this murderous wall, entire sections of Iraqi infantry were simply cut down. Screaming and rattling away with their Kalashnikovs on full auto, they were knocked from their feet with carefully aimed shots. When staggering losses finally broke their spirit, the surviving Iraqis either threw down their weapons or simply ran away. Scattered about lay the bodies of 167 of their comrades. The Iraqi dead lay in mute testimony to the Americans' tenacity and marksmanship skills.

With the criticism of poor terminal performance leveled by many on the 5.56X45mm, you would think those 167 Iraqis were cut down by 7.62X51mm M14s. Such was not the case. They fell to 5.56X45mm MK-12 Mod 0/1 sniper rifles firing 77gr MK-262 Mod 1. Developed to offer increased accuracy, range and improved terminal performance over the standard 62gr M-855 load, the MK-262 Mod 1 has performed quite well in actual combat. This impressive combat record has stimulated a great deal of interest among civilian shooters, so we thought we'd take a look at this load.

When work was undertaken on what was to eventually become the MK-12 series of sniper rifles it was understood from the outset that a better 5.56mm load would be needed. Standard M-855 MP-Ball (Multi Purpose-Ball) was deemed unsuitable due to its accuracy and terminal performance criteria. Manufacturing specifications for this load only require it to shoot into four MOA from 100 to 600 meters. For use at 600+ yards a projectile with a higher ballistic coefficient was desirable to reduce drop and wind drift. The question was how to make the 5.56mm into a viable 600+ yard cartridge.

While competition shooters, or "yellow glasses", are often scorned by the tactical crowd, they laid the ground work in this regard. Loads using 75, 77 and 80gr HPBT match bullets began to dominate service-rifle competition in the late 1990s. One company that was at the forefront of loading extremely accurate and consistent 5.56mm match ammo was Black Hills Ammunition. Its 5.56mm match ammo was so good, from lot to lot, that it had contracts from all the armed forces rifle teams. This was quite a testimony to both Black Hills and its workers. So, Black Hills was contacted about the specific needs and requirements the military had for this new 5.56mm combat load.

Testing was undertaken using a variety of projectiles and powders, with the goal being enhanced accuracy and terminal performance at extended distances. At first a 73gr Berger Open Tip Match bullet was selected, then changed to a 77gr Nosler Open Tip Match bullet. This load with the 77gr Nosler was called the MK-262 Mod 0. This was later changed to a 77gr Sierra MatchKing, and was named the MK-262 Mod 1. Rather than being loaded to commercial .223 Remington pressures, this ammunition was loaded to higher 5.56mm NATO pressures to enhance performance. The resulting load was very similar to match ammunition loaded for the Army Marksmanship Unit for use in competition.

The ML-12's ammunition evolved and was eventually type-classified as MK-262 Mod 0 and Mod 1. The primary difference between the two is the addition of a semi-cannelure to the Mod 1 projectile to prevent bullet setback during feeding.

Both terminal performance and accuracy of this ammunition are markedly improved over M-855 MP-Ball. Each lot is tested for accuracy by firing 10, 10-shot groups at 300 yards. The average group size is between two and two and a half inches. Due to the way the 77gr Sierra MatchKing behaves in soft tissue, this load offers dramatically increased terminal performance compared to the M855; while still being Land Warfare legal. The downside is that penetration is not as good as the M-855 round on harder targets or body armor.

Curious as to how the MK-262 Mod 1 would compare, I arranged to test some out of a MK-12 Mod 0 clone built by Angus Arms. Initial testing was performed from a bench at 100 yards by the rifle's builder, Angus Norcross of Angus Arms. Five-round groups were fired, and velocity was recorded 12 feet from the muzzle with an Oehler 35P chronograph. Five rounds of 62gr M-855 MP-Ball were fired first as a control.

The M-855 grouped into 2.37 inches at an average velocity of 3,044 FPS; unimpressive but within specifications for this load. Switching to Black Hills 77gr MK-262 Mod 1 cut the group size dramatically. Four rounds clustered into less than half an inch, and Norcross put all five into .6 inch. Most impressive was the velocity of this 5.56mm pressure load. The 77gr Sierras were averaging 2,783 fps from the short 18-inch barrel of the MK-12 Mod 0. In comparison a Black Hills .223 Remington-pressure 77gr match load averaged 2,615 FPS from the same rifle.

From the bench we moved to shooting prone from a ridgeline. Conditions were cold, with an ambient temperature of 30 degrees and wind gusts up to 12 mph. A heavy layer of snow covered the ground. After posting targets 300 yards away I proceeded to fire five-shot groups off the bipod.

First up was the M-855, which grouped into a fairly respectable 5.25 inches. Switching to MK-262 Mod 1 cut group size almost in half. This load averaged three inches at this distance. What was most impressive was how controllable and easy to hit with the MK-12 rifle was with this load. Making rapid multiple hits on multiple targets at random distances is simple. The gun simply spits empty cases.

Without a doubt, the MK-262 Mod 1 has proven very effective in actual combat. It's capable of excellent accuracy out to 700+ yards if you can call the wind. Terminal performance is a noticeable step up from M-855. While it was originally intended for use in the MK-12 series sniper rifles, its enhanced terminal performance has led to it being used in M-4 carbines as well. Basically, it's a desirable commodity being used by whatever troops can get their hands on it.

MK-262 Mod 1 Specifications

Manufacturer: Black Hills Ammunition
Caliber: 5.56X45mm NATO
Bullet: 77gr .224" Sierra Match King, Semi-Cannelured
Color Code: None
Casing: Black Hillls 5.56X45mm Match, Sealed for Submerssion, Crimped Primer
Head Stamp: None
Velocity: 2,791 FPS out of an 18" Bbl
Testing Notes: Velocities are an average of 10 rounds recorded 12 feet from the muzzle with an Oehler 35P chronograph at an ambient temperature of 30 degrees fahrenheit at 100 feet above sea level.
 

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The Mark 262 Mod 1 uses the Sierra 77 SMK Canellured, now that Sierra agreed (for the sake of the contract) to run a light canellure on the 77. Both of these are availbale for reference online, and there is zero difference in performance between the two Sierra 77s.

I will note that, having loaded to near Nato spec, attempting to duplicate the load, it is fairly impossible to do with RL-15. Using the 77SMK in NEW LC09 cases, I managed 2,675 in a standard Chromed 16" M4. Not bad, and good on pressure to 115-degree ambient temperature with a hot barrel. I wouldn't go any hotter for fear of blanking primers, and I won't run those in my match rifle either (though it'd probably be okay with the Wylde).

Like they stated, basically all 262 is is our standard highpower load on the steroid of a canister-grade powder. It IS very much more accurate, as I sometimes saw the verge of 3/4 Minute accuracy from an ACOG/M4 with over 10,000 rounds down the tube. Certainly MOA capable.

-Nate
 

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Has anyone tried to duplicate this round using AR Comp as the powder? Alliant's data says their max load is pretty close to the Mk 262 velocities. I've worked up a load, but don't have access to a chronograph to compare it. The accuracy was fantastic (a little over .5 MOA), so I haven't tried to go up yet. I was using 21.9 grn of AR Comp with no signs of pressure. I haven't gone any higher, though I think I probably could go up a little more.
 

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No.

This is thread is 5 years old. Let it die, start a new post. Use google, I am sure you can find a similar recipe.
 

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OH, google, what's that? If you're not interested, you didn't have to participate. I'm sorry; I thought this forum was here so folks could discuss things that interested them. If no one was interested, they'd ignore it completely and it will go away. It's not necessary to be an A$$!
 

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It is also not necessary to start an argument. In a way GMinor has a point. You have to realize that in 5yrs time, many people originally in this thread are no longer present or participating in the forum... The ones that are still here, probably do not remember the conversation. I'm not saying don't be interested, we all have our interests and our questions... Ask away. But do not turn disrespectful over someone simply pointing out it's an old thread... You have been here a week... You currently have 2 posts... Not off to a good start...
 
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Tech, product and ideas have also moved on. Best to start a new thread and if you want, link it to this one out of interest for the back story. Other than that, what Arkansas said.
 

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I am working up some loads with AA 2460 and Hodgdon CFE223. I am using 77 gr Sierras and Noslers. The max for the 77s with 2460 is 2872 fps, with 75gr Hornady is 2885. The loads for CFE223 are topped out at 2811 fps with the 77 gr and 2876 fps with the 75 gr. The CFE223 loads are 223 pressure loads. If they had 5.56 level data for that powder I am sure it will easily make the speed. Waiting for my friend to drop of the chrono and will update my findings. If I get 2650-2700 fps from my 16 inch barrel I will be happy.
 

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So I finally got to chrono some loads! I got tired of waiting and bought me a chrono. I used my 26 inch Savage 12 FV and my 16 inch PSA AR15 for testing. From everything I gathered, 2650 from a 16 inch barrel is what the MK 262 load should shoot. I have seen one source that said 2750, but I don't think that is possible with commercial powders. So I used CFE, BLC2, AA2460, AA2230C. I used the 75gr Hornady Match bullet. I also used the 69 SMK bullet...I was testing the difference between the 2460 and the 2230C powder (Accurate said use 2460 data for both as they are the same). I had some 77 Nosler loads, but ran out of time. Using the 75 gr Hornady bullet, the 2460 shot 2690 fps out of the 16 inch barrel with 20 shots; 2950 fps out of the Savage 26 inch barrel. BLC2 shot 2620 fps and 2800 fps. The CFE was a surprise coming in at 2768 fps and 2992 fps! The 2230C and 2460 was so close as to be identical across the different bullet weights. All the loads showed no high pressure signs in either gun. No loads were max loads. Except the CFE load is lower in the Hodgdon manual than in the Hornady manual...I went with the bullet maker's load. So in my eyes, the MK262 load is not unobtainable by mortals!
 
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Most clutch. I'm sitting on several pounds of cfe and a couple hundred 77gr tmks and have been meaning to work up a load for the spr. What's your load data look like and how did it print on target?
 

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MK262 mod 1 duplicate, try:

77gr Sierra Match King, 25.3gr Varget, CCI 400 primer, and LC brass - NOTE: THIS LOAD EXCEEDS SAAMI SPECS. USE IN NATO OR WYLDE CHAMBER ONLY. USE AT OWN RISK. - 2780~ fps in an 18" SPR barrel.
 
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