What's different in this gun that makes the Canadian version have lower fps than the American version ? I've modified the bolt to push the pellet into the chamber and allow for better air flow and drilled out the transfer port ! Both especially the transfer port made a big difference. I heard there is a pressure relief valve that only allows the gun to hold a certain amount of pressure but don't know if this is true or not ! Could it be the transfer port that slows the fps ? Yes if someone knows where a good place is to buy a flat top piston please let me know. Thanks btw I just want to hear from others that know of and have modified this gun, that's all ! Travis