AirForce Tex-Rex Big Bore Air Rifle Velocity: Up to 1350 FPS w/ a 80 grain round ball in .308 and 1250 FPS w/ a 225 grain slug in .457 and .510 Max Fill Pressure: 4500 psi/310 bar Muzzle energy: up to 450 FPE w/ 205 grain slug in .308 and .457, 1100 FPE w/ 620 grain slug .510 caliber Available in .308, .457, .510 caliber New Titanium Valve System 500cc carbon-fiber air tank Two-stage, position-adjustable trigger Safety: Automatic 34" Lothar Walther barrel Single shot Shots per fill vary based on Bias Port Three Bias Port Screws are included: .067 (pre-installed), .059, and .040 Shot per fill: 6-7 shots in .308, 5-6 shots in .457 caliber and 4-5 shots in .510 caliber Weight: 7.25 lbs Length: 48.75" Weaver/Picatinny rail M-LOK Foregrip Made in the USA Please Note: Before 2026 this gun came with an 11mm dovetail scope rail. It now comes with a Weaver/Picatinny scope rail.