David Tubb's competition wildcat: a mid-size 6mm case optimized for long-range F-Open competition, offering more powder capacity than 6mm BR while staying shorter than 6-284.
Type: Rifle
Introduced: 2005, United States
Parent case: .284 Winchester
Standardization: Wildcat
Bullet diameter: 0.243" (6.17 mm)
Case length: 2.06" (52.32 mm)
Overall length: 2.8" (71.12 mm)
Max pressure: 62,000 PSI
Rim type: Rebated
Primer: Large Rifle
Typical twist rate: 1:8
Muzzle velocity: 3100–3300 fps
Muzzle energy: 2241–2613 ft-lbs
Effective range: 1000 yd
Common bullet weights: 105, 107, 108, 115 gr
Primary use: Competition, Target
Production status: Active
Also known as: 6mm XC · 6-XC
History: Developed around 2005 by David Tubb, 12-time National High Power champion. The 6XC was engineered specifically for F-Open and High Power competition, bridging the gap between the efficient but small 6mm BR and the larger but over-powered 6-284. Superior Shooting Systems (Tubb's company) produces custom brass. The cartridge won numerous national and world titles in F-Open competition throughout…
Notable firearms: Custom F-Class bolt guns, Kelbly Atlas, BAT Machine actions, Borden Rimrock
Similar cartridges: 6mm Creedmoor, 6mm BR Norma, 6GT, 6mm Dasher