- Side
- Ukraine
Canada announced that 1 million rounds of 5.56 mm ammunition and 4,800 assault rifles were scheduled for delivery to Ukraine in the weeks after the May 2023 Ukraine Defense Contact Group meeting.
Role detailsMunitions
5.56x45mm NATO cartridge
Also known as
- 5.56 NATO
- 5.56x45 mm cartridge
- 5.56x45mm NATO
- 5.56 x 45 mm NATO
- 5.56mm NATO
- SS109
- M855
- M855A1
- L110
The 5.56x45mm NATO cartridge is the NATO-standard small-arms cartridge family built around FN Herstal's SS109 lineage, standardized by NATO in 1980 and produced by many ammunition makers. This entry tracks both its technical family context and direct conflict evidence, including Canadian 5.56 mm ammunition supplied for Ukraine, U.S. Army M855A1 fielding in Afghanistan, and 5.56 x 45 mm ammunition recovered from Islamic State forces in Iraq.
Role in Conflicts
The U.S. Army announced in June 2010 that it had begun shipping the M855A1 5.56 mm Enhanced Performance Round to support warfighters in Afghanistan, with soldiers there expected to begin using it that summer.
Role details- Side
- Islamic State
Conflict Armament Research documented 5.56 x 45 mm ammunition loaded in M16A4 magazines captured from Islamic State forces in northern Iraq and heavy concentrations of expended 5.56 x 45 mm ammunition at former Islamic State firing positions near Gwer and Hawerah in August 2014.
Role detailsProfile / Specs
Profile
- Origin
- Belgium / NATO
- Built in
- Belgiummultiple countries
- Type
- 5.56x45mm NATO small-arms cartridge
- Service note
- Late Cold War to present NATO standard rifle ammunition
- Designer
- FN Herstal for the SS109 cartridge lineage adopted as the NATO standard
- Designed
- SS109 standardized by NATO in 1980
- Produced
- 1980 to present for NATO-standard 5.56x45 mm service loads
Specifications
- Caliber
- 5.56x45 mm NATO
- Standard cartridge lineage
- SS109 / M855 ball family
- Representative U.S. improved load
- M855A1 Enhanced Performance Round
- Ammunition types
- SS109 ball, L110 tracer, blank, and service-specific improved ball loads
- Representative projectile weight
- FN technical data lists SS109 ball and L110 tracer projectile weight at about 4 g / 61.7 gr
- Representative velocity
- FN technical data lists approximate 25 m velocities of 915 m/s for SS109 ball and 875 m/s for L110 tracer
- Compatible weapon classes
- Carbines, assault rifles, and light support weapons
- NATO standardization
- FN Herstal says SS109 was adopted by NATO as the second official standardized calibre in 1980
Service Load Structure
The cartridge family appears on this page as a service-ammunition family rather than a single factory load. FN Herstal documents the NATO SS109 baseline and associated tracer and blank loads, while U.S. Army sources document the M855 and M855A1 service-load path.
| Load or designation | Documented role | Source-backed context |
|---|---|---|
| SS109 / M855 | Ball ammunition lineage | FN identifies SS109 as the NATO-standardized cartridge; U.S. Army coverage ties M855 to M249 and M16A2 service. |
| M855A1 | Enhanced performance round | U.S. Army sources describe a 2010 Afghanistan fielding path and compatibility with the M4, M16, and M249 families. |
| L110 and blank | Tracer and training loads | FN lists tracer and blank options in its 5.56x45 mm NATO ammunition range. |
Sources: FN Herstal 5.56x45mm NATO; Army begins shipping improved 5.56mm cartridge; Evolution of the M855A1 Enhanced Performance Round.
Variants
This entry treats 5.56x45mm NATO as a cartridge family. FN Herstal identifies SS109 as the original NATO-standardized 5.56x45 mm military load, while U.S. Army sources document the M855 and M855A1 American service-load path.
| Variant | Configuration | Designation notes |
|---|---|---|
| SS109 / M855 ball | Standard ball load lineage | FN identifies SS109 as its NATO-standardized 5.56x45 mm cartridge; U.S. Army coverage describes M855 as the Army's 5.56 mm round adopted for longer-range performance with the M249 and M16A2. Sources: FN Herstal 5.56x45mm NATO, Evolution of the M855A1 Enhanced Performance Round |
| M855A1 Enhanced Performance Round | U.S. Army improved ball round | The U.S. Army describes M855A1 as a 5.56 mm enhanced performance round tailored for the M4 and improving performance in the M16 and M249 weapon families. |
| L110 tracer | Tracer load | FN Herstal lists L110 as the tracer ammunition type in its 5.56x45 mm NATO range. Sources: FN Herstal 5.56x45mm NATO |
| Blank | Training and simulation load | FN Herstal lists blank ammunition as part of its 5.56x45 mm NATO cartridge range. Sources: FN Herstal 5.56x45mm NATO |
Firing Weapons
Catalog links below are limited to weapons or weapon families with direct source support for a 5.56x45 mm, M855A1, or equivalent 5.56 mm NATO relationship.
| Firing weapon | Weapon type | Firing evidence |
|---|---|---|
 | Carbine | The U.S. Army says the M855A1 5.56 mm round is tailored for use in the M4 weapon system. |
 | Rifle | The U.S. Army says the M855A1 improves performance in the M16 weapon family and traces M855 adoption to M16A2 compatibility. Sources: Army begins shipping improved 5.56mm cartridge, Evolution of the M855A1 Enhanced Performance Round |
 | Light machine gun | FN Herstal lists the FN MINIMI 5.56 as a light support weapon use case for its 5.56x45 mm NATO ammunition. Sources: FN Herstal 5.56x45mm NATO |
 | Self-loading rifle platform | Colt's AR15A4 product page identifies the representative AR-15-pattern rifle as chambered in 5.56x45mm. Sources: AR15A4 Rifle |
 | Assault rifle | Arsenal product pages identify the AR-M9 and AR-M9F rifle family in 5.56x45 mm and 7.62x39 mm configurations. Sources: 5.56x45 mm and 7.62x39 mm AR-M9, 5.56x45 mm and 7.62x39 mm AR-M9F |
Compatible Firearms
| Compatible item | Item type | Compatibility evidence |
|---|---|---|
 | Assault rifle | Small Arms Survey lists the Galil and close derivatives in 5.56x45 mm chambering, documenting the Galil family as compatible with this cartridge. Sources: Galil Weapons Identification Sheet |
 | Assault rifle | Heckler & Koch lists the G36 calibre as 5.56 mm x 45 NATO, documenting direct compatibility with this cartridge. Sources: G36 |
Timeline
5.56x45mm NATO cartridge Key Events
U.S. Army adopts the M16 rifle
U.S. Army historical coverage states that the Army adopted the 5.56 mm M16 rifle in 1967 with the earlier M193 cartridge.
Sources: Evolution of the M855A1 Enhanced Performance Round
NATO standardizes FN's SS109 lineage
FN Herstal identifies the SS109 cartridge as its design and says NATO adopted it as the second official standardized calibre in 1980.
Sources: FN Herstal 5.56x45mm NATO
U.S. Army adopts M855
U.S. Army coverage describes the 1982 adoption of M855 to replace M193 and improve longer-range performance with the M249 Squad Automatic Weapon.
Sources: Evolution of the M855A1 Enhanced Performance Round
M855A1 shipping announced for Afghanistan
The U.S. Army announced that it had begun shipping the M855A1 5.56 mm cartridge to support warfighters in Afghanistan.
Sources: Army begins shipping improved 5.56mm cartridge
Canada announces 5.56 mm ammunition for Ukraine
Canada stated that 1 million rounds of 5.56 mm ammunition were scheduled for delivery to Ukraine as part of a larger small-arms and ammunition aid package.
Sources: Canada May 2023 Ukraine military aid
Media
5.56x45mm NATO cartridge Videos
Related Weapon Systems
Sources
FN Herstal 5.56x45mm NATOPublisher: FN Herstal | Note: Supports manufacturer background, the 5.56x45 mm SS109 designation, NATO standardization in 1980, listed ammunition types, and compatible weapon classes including FN MINIMI 5.56. | Accessed: 2026-07-04FN 5.56x45mm NATO cartridges technical dataPublisher: FN Herstal | Note: Supports technical data for FN 5.56x45 mm NATO cartridge types, including SS109 ball, L110 tracer, blank, projectile weights, and representative 25 m velocities. | Accessed: 2026-07-04Canada May 2023 Ukraine military aidPublisher: National Defence / Canadian Armed Forces | Note: Directly supports the 2014 Russia-Ukraine War row by documenting Canada's scheduled delivery of 1 million rounds of 5.56 mm ammunition to Ukraine. | Accessed: 2026-07-04Army begins shipping improved 5.56mm cartridgePublisher: U.S. Army | Note: Directly supports the 2001 War in Afghanistan row by documenting M855A1 5.56 mm cartridge shipments for warfighters in Afghanistan; also supports M855A1 background, M4/M16/M249 compatibility context, and U.S. Army image provenance. | Accessed: 2026-07-04Evolution of the M855A1 Enhanced Performance RoundPublisher: U.S. Army | Note: Supports U.S. 5.56 mm service-load history, including M16 adoption, M855 adoption, M249/M16A2 compatibility, and M855A1 design context. | Accessed: 2026-07-04Islamic State Ammunition in Iraq and SyriaPublisher: Conflict Armament Research | Note: Directly supports the 2014 War Against the Islamic State row by documenting 5.56 x 45 mm ammunition captured from Islamic State forces in northern Iraq and expended 5.56 x 45 mm ammunition at former Islamic State firing positions near Gwer and Hawerah. | Accessed: 2026-07-04AR15A4 RiflePublisher: Colt's Manufacturing Company | Note: Supports the Colt AR15A4 rifle's 5.56x45mm chambering and representative rifle-cartridge compatibility context. | Accessed: 2026-07-04Galil Weapons Identification SheetPublisher: Small Arms Survey | Note: Supports the Galil family's documented 5.56x45 mm chambering for reciprocal cartridge compatibility. | Accessed: 2026-07-04G36Publisher: Heckler & Koch | Note: Supports the G36's chambering in 5.56 mm x 45 NATO and its direct compatibility with this cartridge. | Accessed: 2026-07-045.56x45 mm and 7.62x39 mm AR-M9Publisher: Arsenal JSCo | Note: Supports manufacturer background for the AR-M9 rifle family and its 5.56x45 mm / 7.62x39 mm product category. | Accessed: 2026-07-045.56x45 mm and 7.62x39 mm AR-M9FPublisher: Arsenal JSCo | Note: Supports manufacturer background for the folding-stock AR-M9F variant and its 5.56x45 mm / 7.62x39 mm product category. | Accessed: 2026-07-04Cartridge 5.56x45mm NATO CC BY-SA 4.0 by Grasyl.jpgPublisher: Wikimedia Commons | Note: Image provenance for the primary 5.56x45 mm cartridge photograph. | Accessed: 2026-07-04Caliber cartridge comparison - .223 Remington and 5.56x45mm NATO.jpgPublisher: Wikimedia Commons | Note: Image provenance for a cartridge comparison image that includes 5.56x45 mm NATO. | Accessed: 2026-07-04