5.7x40mm AVA

5.7x40mm EC
Type	Rifle
Place of origin	Entente Cordiale
Service history
In service	1978–present
Used by	Sieuxerr Sylva New Tyran EC
Wars	Various
Production history
Designer	Saint-Étienne Arms Manufacturer
Designed	1977
Manufacturer	MAS Manurhin Various other plants
Specifications
Case type	Rimless
Bullet diameter	5.7mm (0.224 in)
Neck diameter	6.5mm (0.25 in)
Shoulder diameter	8.3mm (0.32 in)
Base diameter	9mm (.35 in)
Rim diameter	9mm (.35 in)
Rim thickness	1.5mm (.05 in)
Case length	40mm (1.57 in)
Overall length	56.4mm (2.22 in)
Rifling twist	1:12
Primer type	Small rifle
Ballistic performance
Bullet mass/type Velocity Energy 57 gr (4 g) Balle A 2,800 ft/s (850 m/s) 1,300 ft⋅lbf (1,800 J)
Source(s): Arsenal Munitions Test Range

The 5.7x40mm EC is a rimless, bottlenecked, center-fired intermediate cartridge family. Designed in the mid-1970s, the 5.7mm EC and 7x51mm EC cartridges and their weapons would become standardized across the Entente and Entente-aligned nations by the 1980s.