Last reviewed: 2026-04-18 by Jake Terry, FFL07/SOT3, NRA-certified firearms instructor.
IMI M855 5.56x45mm NATO ammunition ships 1200 rounds of 62-grain SS109 penetrator full metal jacket projectiles — the NATO-qualified green tip load built for AR-15 rifles with 1-in-7-inch twist barrels. Established in 1933, IMI Systems specializes in defense ammunition qualified by the Israel Defense Forces, U.S. Military branches, and NATO nations. Each round leaves a 24-inch test barrel at 3020 feet per second, delivering 1256 foot-pounds of muzzle energy. The SS109 bullet pairs a steel penetrator tip with a lead core, finished with the signature green paint marking that designates penetrator-tipped ammunition under STANAG 4172 specifications. You load boxer-primed, reloadable brass cases with no corrosive primers — 40 boxes of 30 rounds each, sized to fill standard AR magazines without leftover rounds.
Built for the Box
IMI loads the M855 to meet all STANAG 4172 and NATO Partnership for Peace requirements, ensuring compatibility with M16A2, M4, and Tavor rifles. The 62-grain projectile stabilizes in barrels with 1-in-7-inch or faster twist rates, common in modern AR-15 platforms issued to military and law enforcement. Brass cases accept standard large rifle primers during reloading cycles. The non-corrosive boxer primer eliminates post-range cleaning urgency, though lead content in the core requires standard ventilation during indoor range sessions. Supersonic velocity rating confirms the load stays above 1125 fps well past 100 yards, maintaining flat trajectory for known-distance drills. Country of origin: Israel. Shipping weight: 33.16 pounds per 1200-round case.
Specs at a Glance
| Spec | Value |
|---|---|
| Caliber | 5.56x45mm NATO |
| Bullet weight | 62 grains |
| Bullet type | SS109 Penetrator Full Metal Jacket |
| Muzzle velocity | 3020 fps |
| Muzzle energy | 1256 ft-lbs |
| Test barrel length | 24 inches |
| Rounds per box | 30 |
| Total quantity | 1200 rounds (40 boxes) |
| Case | Brass |
| Primer | Boxer, non-corrosive |
| Reloadable | Yes |
| Velocity rating | Supersonic |
| Intended use | Range & Target |
| Country of origin | Israel |
| Lead free | No |
The M855 load runs at higher chamber pressures than commercial .223 Remington — fire only in rifles marked 5.56 NATO or 5.56/.223 Wylde. Confirm your barrel twist before ordering: 1-in-7-inch stabilizes the 62-grain projectile optimally, while 1-in-9-inch or slower twists may keyhole at extended distances. For bulk range work and carbine drills on AR platforms, browse our full M855 green tip 5.56×45 ammo inventory for additional load options and case quantities.
Safe Handling & Compliance
Federal law requires purchasers to be at least 18 years old for rifle and shotgun ammunition, and at least 21 for handgun ammunition. Ammunition cannot be shipped to certain states, counties, and cities — review our ammunition shipping restrictions before ordering. Store ammunition in a cool, dry location away from heat sources and out of reach of unauthorized users.
- Treat every firearm as if it is loaded; keep muzzle pointed in a safe direction; finger off trigger until sights on target; know your target and what lies beyond.
- Verify current state and local ammunition purchase laws in your jurisdiction — some areas restrict penetrator-tip ammunition or bulk purchases.
- Store M855 ammunition away from moisture and temperature extremes; lead-core projectiles require standard ventilation during indoor range use — see California Proposition 65 warnings.
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