5.56×45mm NATO

Federal 5.56x45 - 62 gr FMJ XM855

Federal 5.56×45 – 62 gr FMJ XM855 – Courtesy Lucky Gunner

*5.56x45mm NATO Overview:

The 5.56×45mm NATO is an intermediate cartridge developed in the United States and originally chambered in the M16 rifle. Under STANAG 4172, it is a standard cartridge for NATO forces as well as many non-NATO countries. It is derived from, but not identical to, the .223 Remington cartridge. If the bullet impacts at high enough velocity and yaws in tissue, fragmentation creates a rapid transfer of energy which can result in dramatic wounding effects.

*5.56x45mm NATO Specs:

  • In Service: Since 1962
  • Designer: Remington Arms
  • Parent Case: .223 Remington
  • Case Type: Rimless, bottleneck
  • Bullet Diameter: 5.70 mm (0.224 in)
  • Neck Diameter: 6.43 mm (0.253 in)
  • Shoulder Diameter: 9.00 mm (0.354 in)
  • Base Diameter: 9.58 mm (0.377 in)
  • Rim Diameter: 9.60 mm (0.378 in)
  • Rim Thickness: 1.14 mm (0.045 in)
  • Case Length: 44.70 mm (1.760 in)
  • Overall Length: 57.40 mm (2.260 in)
  • Case Capacity: 1.85 cm3 (28.5 gr H2O)
  • Rifling Twist: 178 mm or 229 mm (1 in 7 in or 9 in, originally 1 in 14 in)
  • Primer Type: Small rifle
  • Maximum Pressure (EPVAT): 430.00 MPa (62,366 psi)
  • Maximum Pressure (SCATP 5.56): 380.00 MPa (55,114 psi)

*5.56x45mm NATO Cartridge Dimensions:

556x45mm NATO Cartridge Dimensions

556x45mm NATO Cartridge Dimensions – All sizes in millimeters (mm)

* courtesy Wikipedia