CZ 455 M2 (.17 Mach2,) WF (with flutes), TH (threaded muzzle-end w/protective cap) Solid anodize .920 Barrel. 

Gun Barrel Stock: 6061 high-quality aircraft aluminum

Barrel Length: 16.5" CZ barrels with threaded muzzle ends. Rifle liner runs the full length in barrels.

Standard Features: Barrel flutes (long one on top, 2 smaller ones on the sides and one on the bottom). 1/2" x 28 TPI threads with threaded protective cap.

Diameter: .920 Bull Barrel Style

Shank Size: .001 Oversized (may require minor hand fitting)

Chamber: M2 - .17HM2 (Mach2) Chamber - can use standard or match grade ammunition. Hyper-velocity ammo, such as CCI Stingers are not recommended.

Liner: 4140 Steel - Button rifled

.050 Thickness on LR & WMR (Magnum) liner, 6 groove

Rate of Twist: 1:9

Caliber: .17 Mach2

Weight: Approximately 1 oz. per inch per length of the barrel

Anodizing: This is an electrochemical process that chemically infuses the color into the aluminum and will not chip, peel or scratch.