Good discussion.

I enjoy the following article. I'd like to work up a few loads using Sierra 77 grain MatchKing bullets and see how well they fare on paper.


Black Hills' Mk 262 Mod 1
How our improved 5.56 stacks up against its peers
By: David Fortier

A specialized 5.56 load developed for use in the Mk 12 sniper rifle, the Mk 262 Mod 1 has proven very effective in combat.

When a five-man Special Forces team looking for Scuds in Iraq 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 Americans 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 by 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 skill.

With the criticism of poor terminal performance leveled by many on the 5.56x45, you would think those 167 Iraqis were cut down by 7.62mm M14s. Such was not the case. They fell to 5.56 Mk 12 sniper rifles firing 77-grain Mk 262 Open Tip Match ammunition. Developed to offer increased accuracy, range and improved terminal performance over the standard 62-grain M855 load, the Mk 262 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 and its Russian and Chinese counterparts.

The Mk 12 series of sniper rifles is capable of providing both precision fire and full-automatic support fire. It’s a surprisingly accurate weapon. The Mk 12 is a collection of parts assembled for the Navy and is not now for sale.

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 5.56 load would be needed. Standard M855 ball was deemed unsuitable due to its accuracy 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 5.56 into a viable 600-plus-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 80-grain 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 5.56 match was Black Hills Ammunition. Its 5.56 match 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 5.56 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 73-grain Berger Open Tip Match bullet was selected, but this was later changed to a 77-grain Sierra MatchKing. Rather than being loaded to commercial .223 Remington pressures, this ammunition was loaded to higher 5.56 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 Mk 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 cannelure to the Mod 1 projectile to prevent bullet setback during feeding.

Both terminal performance and accuracy of this ammunition are markedly improved over M855 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 77-grain 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 M855 round.

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 M855 ball. While it was originally intended for use in the Mk 12 series, its enhanced terminal performance has led to it being used in M4 carbines as well. Basically, it's a desirable commodity being used by whatever troops can get their hands on it.

The Mk 262 Mod 0/1 ammunition is based on lessons learned by competition shooters using the 5.56 at 600 yards.