$160.00–$1,280.00Price range: $160.00 through $1,280.00
Atomic Ammunition 5.56 NATO 77gr MK262 HP BT defense ammo delivers mil-spec accuracy and terminal performance in the proven MK262 configuration trusted by special operations units.
Caliber: 5.56 NATO
Bullet: 77gr Hollow Point Boat Tail (MK262 spec)
Velocity: 2,750 fps
Energy: 1,294 ft-lbs at muzzle
Accuracy: Sub-MOA in quality AR-15 platforms
Application: Home defense, duty use, 3-Gun competition
Buy 5.56 MK262 ammo from Atomic Ammunition. Our 77gr hollow point boat tail mirrors the MK262 Mod 1 load developed for U.S. special operations — a heavier 5.56 round that delivers superior accuracy and terminal effect compared to standard 55gr M193 or 62gr M855. This is 5.56 defense ammo built for shooters who demand more from their AR-15 than ball ammunition can deliver.
Performance Specifications
Specification
Details
Caliber
5.56 NATO
Bullet Weight
77 grains
Bullet Type
Hollow Point Boat Tail (HP BT) — MK262 configuration
Muzzle Velocity
2,750 fps
Muzzle Energy
1,294 ft-lbs
Accuracy
Sub-MOA in quality firearms
Barrel Twist
1:7 or 1:8 recommended for 77gr stabilization
Casing
New brass — boxer-primed, reloadable
Application
Home defense, duty, 3-Gun, long-range AR
Terminal Performance & Self-Defense
The 77gr HP BT outperforms standard M193 and M855 in every metric that matters for defense: accuracy, terminal effect, and barrier performance. The heavier bullet maintains velocity and energy at distance, making it effective out to 600+ yards in competition use. For home defense and duty, the hollow point design provides controlled expansion while the 77gr weight reduces deflection through intermediate barriers like drywall and auto glass. This is the same weight class used by SOCOM for a reason — it works.
American-Made Components & Quality
Loaded with premium American-made components: new brass cases, precision-weighed powder charges, and match-grade 77gr HP BT projectiles. Each round is inspected to ensure the tight tolerances required for sub-MOA consistency. Atomic manufactures to duty-grade standards — this is ammunition you can trust your life to.
Frequently Asked Questions
Will 77gr stabilize in my 1:9 twist barrel?
77gr bullets require faster twist rates. We recommend 1:7 or 1:8 twist barrels for optimal stabilization. A 1:9 twist may not fully stabilize the bullet, reducing accuracy.
How does this compare to M855 green tip?
MK262-type ammo is more accurate, has better terminal performance, and is less prone to over-penetration than M855 ball. M855 was designed for penetration, not terminal effect.
Is this safe for home defense?
Yes. The 77gr HP BT provides controlled expansion, reducing over-penetration risk compared to FMJ or steel-core ammunition.
Is the brass reloadable?
Yes. New boxer-primed brass, fully reloadable.
What is the minimum order?
Minimum order is 100 rounds. Bulk discounts on 200+ rounds.
