The rifle may be detuned a number of different ways- lower-pressure gas strut installed, different length piston (i.e. change amount of air movement as a result), vent holes drilled in the piston, or any combination of these- you would need to take it apart, look things over and put tension on the strut (i.e. determine how much force is required to compress it fully) to see what was done on your specific rifle. All the rifles of this platform are actually made in China for Crosman, and the Chinese assembly line will alter the detune method depending on what parts they have available at any given moment, and as long as it is below 495fps (often, things are closer to 450fps) and is of sufficient quality otherwise, Crosman accepts it.

If you want to upgrade it to its full-power state at some point (i.e. when you have a PAL if you don't have one already), you can use this kit, which contains all the parts that may be altered/changed in a detuned rifle: http://scopesandammo.com/storefront/...pair-kit-p-837