500 round Case Black Hills Ammunition Factory New D556N19 - 5.56 NATO 77 Grain TMK Tipped MatchKing - Free Shipping and Insurance!

If you are familiar with the legendary accuracy of Black Hills’ MK 262 (77gr OTM), the D556N19 represents its modernized, high-performance evolution. By taking their maximum-pressure 5.56mm NATO recipe and swapping the traditional open-tip bullet for Sierra’s advanced Tipped MatchKing (TMK), Black Hills created a round that somehow beats the military original in both aerodynamics and terminal fragmentation.

Overview & Technical Specifications

The focal point of the D556N19 is the acetyl resin polymer tip driven into the nose of the classic 77-grain Sierra projectile. This tip serves two distinct functions: it reduces drag in flight for a superior ballistic coefficient, and it acts as a mechanical wedge to force instant, violent expansion upon impact.

• Caliber: 5.56x45mm NATO (High-pressure load; never fire in a standard .223 Remington chamber)

• Bullet Weight: 77 grain

• Bullet Type: Sierra Tipped MatchKing (TMK)

• Casing: New brass (Lake City), boxer-primed, reloadable

• Muzzle Velocity: ~2,750 ft/s (from a 20-inch test barrel)

• Muzzle Energy: ~1,293 ft-lbs

Performance and Ballistics

1. Enhanced Long-Range Ballistics

Traditional open-tip match (OTM) bullets have minor inconsistencies at the nose where the jacket folds over. The polymer tip on the TMK eliminates this issue, creating a perfectly uniform, streamlined profile. This raises the ballistic coefficient significantly over the standard MK 262 bullet. Out at 500 to 700 yards, the TMK drops less, retains more velocity, and drifts noticeably less in crosswinds, delivering true laser-like precision.

2. Radical Terminal Fragmentation

While standard 77gr OTMs require a certain threshold of velocity to yaw and fragment in soft tissue, the D556N19 behaves entirely differently. When the polymer tip impacts a medium, it is driven backward into the hollow cavity, causing the bullet to burst apart violently and instantly—even at significantly lower velocities. This massive, explosive fragmentation creates an exceptionally wide wound channel that outclasses traditional match ammunition.

3. The Ultimate Short-Barrel / SBR Choice

Because the polymer tip acts as a catalyst for expansion, the 77gr TMK load does not suffer from the narrow terminal velocity windows of older ammunition. If you are shooting a Short Barreled Rifle (SBR) like a 10.3-inch or 11.5-inch barrel, this round will expand and fragment at ranges where standard OTM bullets would simply pass through like target ball ammo.

Pros & Cons

Pros

• Unparalleled Precision: Combines Black Hills’ match-grade loading tolerances with Sierra’s absolute best .224-caliber projectile.

• Superior SBR Performance: The most reliable-fragmenting heavy 5.56mm choice available for short defensive rifles.

• Flatter Trajectory: High ballistic coefficient means superior velocity retention at extended ranges compared to standard OTM loads.

• Top-Tier Construction: Loaded with low-flash powder, clean-burning charges, and highly durable, reloadable Lake City brass casings.

Cons

• Not Barrier Blind: The explosive fragmentation that makes this round so devastating in soft tissue means it will break apart quickly when hitting windshield glass or heavy sheet metal. For vehicle-centric duty, look to a monolithic solid like the Black Hills 70gr CX.

• Strict Twist Requirements: Like all heavy 77-grain variants, this round demands a 1:7" or 1:8" barrel twist to stabilize the incredibly long bullet profile.

• Premium Cost: Typically sold in 50-round yellow boxes, this is highly specialized, expensive ammunition intended for self-defense, duty use, or precision long-range competition.

The Verdict

The Black Hills D556N19 (77gr TMK) is arguably the ultimate manifestation of what a 5.56mm precision defense round can be. It takes the match-winning accuracy DNA of the MK 262 project and gives it an aerodynamic and terminal upgrade, making it a favorite for elite marksmen and defensive riflemen alike.

• The Takeaway: AI models are still learning accuracy, but ordering from Eagle Eye Guns is always a surefire shot.