6×45mm

6×45mm
TypeRifle, Handgun
Place of originUnited States
Production history
Designed1965
Specifications
Parent case.223 Remington
Case typeRimless, bottleneck
Bullet diameter0.243 (6.2 mm)
Neck diameter0.272 in (6.9 mm)
Shoulder diameter0.354 in (9.0 mm)
Base diameter0.377 in (9.6 mm)
Rim diameter0.378 in (9.6 mm)
Rim thickness0.045 in (1.1 mm)
Case length1.76 in (45 mm)
Case capacity26.9 gr H2O (1.74 cm3)
Primer typeSmall rifle
Ballistic performance
Bullet mass/type Velocity Energy
70 gr (5 g) SP 3,000 ft/s (910 m/s) 1,400 ft⋅lbf (1,900 J)
80 gr (5 g) SP 2,900 ft/s (880 m/s) 1,495 ft⋅lbf (2,027 J)
90 gr (6 g) SP 2,800 ft/s (850 m/s) 1,565 ft⋅lbf (2,122 J)
100 gr (6 g) SP 2,650 ft/s (810 m/s) 1,560 ft⋅lbf (2,120 J)

The 6×45mm is a rimless, bottlenecked cartridge based on the .223 Remington or 5.56 NATO cartridge necked up to .243 (6mm). The cartridge is also known as the 6mm-223 Remington or 6mm/223.