if your vel. is under 495 with 8 gr pellets you need new sleals. The 300 as it stands will hang in there with anything around. During its heyday it was the preferred choice for Olympic competitors. I have seen a few shoot slightly above 600 fps the avg. is 550-75 fps wich is the most stable velocity range for the pellets/competition it was designed for ( 10 meter ISU ). I have never seen or heard of any type of gas ram modification for these. It is not a dual pistion design. the action slides back to absorb recoil. The RWS 75 series was a dual piston design to negate recoil. I forget the specific design names. The more vel. you have with a springer the more unruly it will become off the bench due to the mass of the piston and torque of the spring decompressing during the firing cycle. hope this helps some.