460 Rounds in Mil-Pack Ammo Can Black Hills Ammunition MK262 MOD 1-C - 5.56 NATO 77 Grain Sierra MatchKing OTM in 20 round boxes - Commercial version of the MK262 Mod1 used by U.S. Military - FREE SHIPPING AND INSURANCE!

If you are looking at this specific SKU, you aren't just looking for standard rifle ammunition—you are looking at a commercial packaging of one of the most famous precision military rounds ever created. The MP460556N9 SKU specifically designates a sealed M19A1 military ammo can containing 460 rounds (packed into 23 individual 20-round boxes) of Black Hills’ civilian-available MK 262 MOD 1-C.

Overview & The MK 262 Legacy

In 1999, at the request of the U.S. Navy, Black Hills developed a precision 5.56mm round designed to stretch the effective range of the M16/M4 platform and maximize the potential of the Mk 12 Special Purpose Rifle (SPR). The result was the MK 262.

The "C" in MOD 1-C stands for Commercial. Black Hills builds this specific line to the exact same high-pressure military construction and performance specs as the rounds they supply to Special Operations forces.

• Caliber: 5.56x45mm NATO (Not safe for .223 Rem chambers due to high pressure)

• Bullet Weight: 77 grain

• Bullet Type: Sierra MatchKing (SMK) Open Tip Match (OTM) with a cannelure

• Casing: Brass (frequently utilizing military-grade Lake City brass), boxer-primed, reloadable

• Muzzle Velocity: ~2,750 ft/s (from an 18-inch barrel)

• Muzzle Energy: ~1,293 ft-lbs

Performance and Accuracy

1. The .64 MOA Guarantee

Black Hills subjects the MOD 1-C to a punishing, no-nonsense lot acceptance test: 10 groups of 10 shots each at 300 yards. No lot is allowed to ship unless it shoots sub-2-inch groups at 300 yards. That equates to a maximum threshold of 0.64 MOA. Out of a quality barrel with a proper twist rate, this ammunition routinely shoots well under a half-MOA, rivaling the absolute finest handloads.

2. Barrel Twist Requirements

Because a 77-grain projectile is quite long and heavy for a .224 caliber, it requires a fast twist rate to stabilize in flight.

• 1:7" or 1:8" Twist: Absolute perfection. It stabilizes beautifully and will reach out past 600–700 yards with high wind resistance.

• 1:9" Twist: Marginal. Some rifles will stabilize it; others will experience "keyholing" (where the bullet tumbles in mid-air).

• 1:12" Twist: Do not use. The slow twist will fail to stabilize the heavy bullet entirely.

3. SBR (Short Barreled Rifle) Performance

While originally optimized for the 18-inch barrel of the Mk 12 SPR, the MK 262 became incredibly popular with operators running short 10.3-inch (Mk 18) barrels. Standard 55gr M193 or 62gr M855 ammunition relies on massive velocity to fragment and create terminal damage—velocity that is lost when you chop a barrel down. Because the 77gr OTM is heavy and long, it fragments much more reliably at the lower velocities produced by short barrels, making this an excellent choice for an SBR defensive load.

Pros & Cons

Pros

• Match-Grade Accuracy: Arguably the most inherently accurate factory-loaded 5.56mm ammunition on the planet.

• Superb Long-Range Ballistics: The heavy 77gr Sierra MatchKing projectile boasts a high ballistic coefficient, meaning it retains velocity further and resists wind deflection far better than standard 55gr or 62gr ammunition.

• Strict Lot Consistency: Buying the 460-round sealed can ensures all your ammunition comes from the exact same factory lot, minimizing any point-of-impact shift.

• Excellent Terminal Effects: Though designed for target accuracy, the OTM design fragments violently upon impact in tissue, making it devastating for defense.

Cons

• Cost: This is a top-tier, premium product. At a price that often hovers around $1.60+ per round, it is far too expensive for casual plinking or range-day blasting.

• High Pressure Warning: This is a true, hot-loaded 5.56mm NATO round. It should never be fired out of older bolt-actions or rifles stamped exclusively for .223 Remington, as it can cause over-pressure signs like blown primers.

The Verdict

The Black Hills MK 262 MOD 1-C (MP460556N9) is widely considered the "gold standard" of heavy 5.56mm ammunition. It successfully bridges the gap between match-grade precision and tactical combat reliability.

Recommendation: If you are a precision shooter, an "SPR" cloner, or someone building a hard-use defensive rifle and you want to see exactly how accurate your platform can be, this is the ammo to buy. Keep a couple boxes stowed away for defensive use or long-range matches, and use cheaper ammunition for your daily range practice.