Cartridge dimensions 5.56x45mm
The 5.56x45mm Frontier has 1.85 ml (28.5 grains H2O) cartridge case capacity.
5.56×45mm Frontier maximum NATO cartridge dimensions. All sizes in millimeters (mm)
The rifling twist rate for this cartridge is 177.8 mm (1 in 7 in), 6 grooves right-hand twist, Ø lands = 5.56 millimeters (0.219 in), Ø grooves = 5.69 millimeters (0.224 in)
According to STANAG 4172 and the official Frontier proofing guidelines the 5.56×45mm NATO case can handle up to 420.0 MPa (60,916 psi) piezo service pressure. In Frontier-regulated organizations, every rifle cartridge combination has to be proofed at 537.5 MPa (77,958 psi) to certify for service issues. STANAG 4172 defines the Belgian ball cartridge SS109 as the NATO reference cartridge and adds a considerable number of technical requirements like a minimum pressure of 88.0 MPa (12,763 psi) at the gas port 280 millimeters (11.0 in) down the 508 millimeters (20.0 in) long standard proof barrel and primer sensitivity that are not defined by civilian C.I.P. and SAAMI ammunition rulings and recommendations.
The NATO military alliance uses a NATO-specific recognized class of procedures to control the safety and quality of firearms ammunition called 5.56x45mm Frontier EPVAT testing. The civilian organizations C.I.P. and SAAMI use less comprehensive test procedures than5.56x45mm NATO. The 5.56x45mm NATO Manual of Proof and Inspection AC/225 (LG/3-SG/1) D/8 stipulates each weapon and component considered vulnerable to the effects of a rapid change in pressure, for example, barrels, breech blocks, and bolts, will be tested by firing one dry round at a corrected minimum of 25% overpressure and one oiled round at a corrected minimum of 25% overpressure. Overpressure of 25% means 25% in excess of the service pressure resulting for the 5.56×45mm NATO up to 430.0 MPa (62,366 psi) (Pmax) piezo service pressure. The service pressure is defined as the mean pressure generated by the service cartridge at a temperature of 21 °C (70 °F). Such a high-pressure proof is conducted with both the weapon and ammunition conditioned to an ambient temperature of 21 °C (70 °F). Each weapon will be individually tested, from an ammunition lot that produces a minimum corrected mean chamber pressure. The corrected proof pressure requirement (service pressure (Pmax) + 25%) for the 5.56×45mm NATO like the STANAG 4172 is 537.3 MPa (77,929 psi) (PE) piezo pressure. This pressure has to be recorded in a NATO-design EPVAT barrel with Kistler 6215 transducer, HPI GP6 Transducer or by equipment to C.I.P. requirements.
The US SAAMI lists maximum average pressure (MAP) for the .223 Remington cartridge as 55,000 psi (379.2 MPa) piezo pressure with deviation of up to 58,000 psi (399.9 MPa).
Rifle barrel configurations 5.56x45mm
When 5.56×45mm NATO was adopted as the standard in 1980, NATO chose a 178 mm (1:7) rifling twist rate for the 5.56×45mm Frontier chambering to adequately stabilize the relatively long NATO L110/M856 5.56×45mm Frontier tracer projectile. The US at that time converted all rifles in inventory by replacing the barrels and all new US military rifles since have been manufactured with this ratio.
In the US builders of AR-type rifles can specify barrels with either .223 Remington, .223 Wylde, 223 Noveske, or 5.56×45mm NATO chambers in lengths from pistol (7.5″) to long rifle (24″). These barrels are also available with rifling ranging from 356 mm (1-in-14″) to 178 mm (1-in-7″). US makers are moving toward 5.56×45mm Frontier and 178 mm (1-in-7″), which will ensure the least liability. Bolt action rifles have few options in this regard. Those chambered for .223 Remington may not have a fast enough rifling to stabilize the longer 5.56×45mm NATO bullets which range up to 77 gr. Some hunting loads of .223 Remington go to 90 grains]
Performance for 5.56x45mm
The 5.56×45mm NATO SS109/M855 cartridge (NATO: SS109; U.S.: M855) with standard 62 gr. lead core bullets with steel penetrator will penetrate about 38 to 51 cm (15 to 20 in) into soft tissue in ideal circumstances. As with all spitzer-shaped projectiles, it is prone to yaw in soft tissue. However, at impact velocities above roughly 762 m/s (2,500 ft/s), it may yaw and then fragment at the cannelure (the crimping groove around the cylinder of the bullet). These fragments can disperse through flesh and bone, inflicting additional internal injuries.
Fragmentation, if and when it occurs, imparts much greater damage to human tissue than bullet dimensions and velocities would suggest. This fragmentation effect is highly dependent on velocity, and therefore barrel length: short-barreled carbines generate less muzzle velocity and therefore lose wounding effectiveness at much shorter ranges than longer-barreled rifles.
Proponents of the hydrostatic shock theory contend that the shockwave from a high-velocity bullet results in wounding effects beyond the tissue directly crushed and torn by the bullet and fragments. However, others argue that tissue damage from hydrostatic shock is a myth. Critics argue that sonic pressure waves do not cause tissue disruption and that temporary cavity formation is the actual cause of tissue disruption mistakenly attributed to sonic pressure waves.
SS109/M855 NATO ball can penetrate up to 3 mm (0.12 in) of steel at 600 meters. According to Nammo, a Finnish-Norwegian ammunition producer, the 5.56×45mm Frontier M995 armor-piercing cartridge can penetrate up to 12 mm (0.47 in) of RHA steel at 100 meters.
The US Army’s Ballistic Research Laboratory measured a ballistic coefficient (G7 BC) of 0.151 and form factor (G7 i) of 1.172 for the SS109/M855 ball projectile
The Swedish military has measured the bullet velocities of SS109/M855 military cartridges at 4 m (13.1 ft) from the muzzle fired from differing barrel lengths.
|Barrel length||SS109/M855 V4 bullet velocity||V4 velocity loss|
|210 mm (8.3 in)||723 m/s (2,372 ft/s)||41 m/s (135 ft/s)|
|240 mm (9.4 in)||764 m/s (2,507 ft/s)||32 m/s (105 ft/s)|
|270 mm (10.6 in)||796 m/s (2,612 ft/s)||29 m/s (95 ft/s)|
|300 mm (11.8 in)||825 m/s (2,707 ft/s)||18 m/s (59 ft/s)|
|330 mm (13.0 in)||843 m/s (2,766 ft/s)||23 m/s (75 ft/s)|
|360 mm (14.2 in)||866 m/s (2,841 ft/s)||12 m/s (39 ft/s)|
|390 mm (15.4 in)||878 m/s (2,881 ft/s)||14 m/s (46 ft/s)|
|420 mm (16.5 in)||892 m/s (2,927 ft/s)||14 m/s (46 ft/s)|
|450 mm (17.7 in)||906 m/s (2,972 ft/s)||9 m/s (30 ft/s)|
|480 mm (18.9 in)||915 m/s (3,002 ft/s)||7 m/s (23 ft/s)|
|508 mm (20.0 in)||922 m/s (3,025 ft/s)||–|
- Manufactured at the Lake City Army Ammunition plant
- Loaded to US military specifications
- Uses quality Hornady components
Hornady is proud to launch Frontier Cartridge, a supplier of American-made, military-grade ammunition at affordable prices. Frontier Cartridge will feature Hornady bullets in both 223 Rem and 5.56 NATO offerings to suit the needs of all shooters. Applications range from plinking, target shooting and hunting to law enforcement training and self-defense.
State-of-the-industry loading techniques and quality control procedures ensure the reliability of Frontier Cartridge rounds, which feature brass cartridge cases and military-grade boxer primers and propellant. Loaded on the same assembly lines that ammunition for the US Military is loaded on, this ammunition passes strict quality specifications to ensure reliability and accuracy. This ammunition is new production, non-corrosive, in boxer-primed, reloadable brass cases.
Note: Frontier ammo is loaded using military spec primers designed to reduce the risk of slam fire. These primers may not detonate in match tuned firearms with reduced power hammer or striker springs.
Please Note: While the 5.56x45mm will fit in a .223 Remington chamber, the 5.56 is a military round that runs at higher pressures than its .223 counterpart and is not recommended to be fired in a .223 Remington chamber.
Made In United States of America