.257 Roberts

Key specs

Type

Rifle

Origin

United States

Designer

Ned Roberts

Introduced

1934

Case type

rimless, bottleneck

Bullet diameter

6.53 mm

Case length

56.72 mm

Overall length

70.49 mm

Typical bullet

75 gr

Typical velocity

1,052 m/s

Typical energy

2,689 J

Parent case

7×57mm Mauser