Wildcat improvement of 6mm BR Norma with a sharper 40-degree shoulder, optimized for F-Class and precision bolt-gun competition. Renowned for high accuracy and very long barrel life.
Type: Rifle
Introduced: 1999, United States
Parent case: 6mm BR Norma
Standardization: Wildcat
Bullet diameter: 0.243" (6.17 mm)
Case length: 1.56" (39.62 mm)
Overall length: 2.8" (71.12 mm)
Max pressure: 58,000 PSI
Rim type: Rimless
Primer: Small Rifle
Typical twist rate: 1:7.5
Muzzle velocity: 2900–3050 fps
Muzzle energy: 1780–2000 ft-lbs
Effective range: 1000 yd
Common bullet weights: 95, 103, 105, 107, 108, 109, 110 gr
Primary use: Competition, Target
Production status: Active
Also known as: 6 Dasher · 6BR Improved · 6mm BR Dasher
History: Created around 1999 by F-Class competitors Dan Dowling and Lou Murdica by fire-forming 6mm BR Norma brass to a sharper shoulder angle. The improved case geometry reduces powder column movement and slightly increases capacity, resulting in more consistent velocities and tighter standard deviations — the holy grail for long-range competition. It dominated F-Open and F-TR competition for years and…
Notable firearms: Custom bolt guns, Kelbly Atlas, BAT Machine actions, Barnard actions
Similar cartridges: 6mm BR Norma, 6GT, 6mm Creedmoor, 6 BRA