Legendary benchrest and long-range competition wildcat. Dominated 1000-yard competition for decades. Extreme accuracy with high velocity. Barrel burner.
Type: Rifle
Introduced: 1960, United States
Parent case: .284 Winchester
Standardization: Wildcat
Bullet diameter: 0.243" (6.17 mm)
Case length: 2.17" (55.12 mm)
Overall length: 2.8" (71.12 mm)
Max pressure: 62,000 PSI
Rim type: Rebated
Primer: Large Rifle
Typical twist rate: 1:8 to 1:10
Muzzle velocity: 3200–3500 fps
Muzzle energy: 2500–3100 ft-lbs
Effective range: 800 yd
Common bullet weights: 80, 95, 105, 107, 115 gr
Primary use: Competition, Target
Production status: Limited
Also known as: 6-284 Winchester · 6mm-284 Win
History: Developed in 1960s by benchrest shooters seeking extreme accuracy. Necking .284 Winchester to 6mm created high-velocity, high-capacity case in short action. Dominated long-range competition for 30+ years. Never commercialized but remained popular wildcat. Inspired development of 6.5-284 Norma. The 6mm Creedmoor is essentially a commercial version of this concept. Still used by some long-range…
Notable firearms: Custom benchrest rifles, Custom long-range competition rifles
Similar cartridges: 6mm Creedmoor, 6.5-284 Norma, .243 Winchester