Cobra Venom Shop takes the Benjamin 392 - 397 fully removes the valve and preforms their magic in our machine shop. the results is 800 fps in .22 cal and 900 fps in .177 caliber. With the tune you can receive 685 fps in .22 with only 5 pumps instead of 8-10 

Benjamin Air Rifle 392 Bolt Action Pump This rifle will go down in history. Expect a similar look, fit, and feel as the 397, but in a larger caliber size. The barrel is finished in black. Model 392 The feel and heft, the balance and precision are exactly what you'd expect from any fine rifle.

At 33 feet, it can deliver a half inch group. Factory drilled and tapped for installation of Williams receiver-mounted peep sight. Push-pull safety, right under your thumb. Bolt cocks rifle and closes breech. Recessed trigger guard. Genuine Hardwood stock and fore-end. Open rear sight, fully adjustable elevation and windage. Action construction entirely of corrosion-resistant, quality brass. Variable pump pellet gun

.22 cal 800 fps Benjamin 392
.177 Cal 900 fps Benjamin 397