Snowy Mountain Rifle Company Bear Pre-Fit for Impact Precision 737R, 777R NBK. Bear Pre-Fit barrels are precision machined, pre-fit for Impact Precision receivers. Specifications: Caliber 65 Creedmoor, length 26 inches, straight taper 1.20, twist 1:7.5, shank 1.20. Material: chrome-moly steel. This pre-fit barrel is designed for high accuracy builds and has been matched to work with Impact Precision 737R, 777R NBK components.