In this Filed Test Review of the Crosman NightStalker .177 caliber pellet shooting air rifle I shoot 5 rounds through the Chronograph to get a real world average FPS of this detuned Canadian version. As expected the CX4 Storm replica does not get anywhere close the 580 FPS the non-regulated version claims to get and even with fairly light 6.9 grain pellets I got an average of just over 400 FPS, also keep in mind I have re-tuned this air rifle a bit to get somewhat higher Feet Per Second performance then the stock Canadian version even if it's not a lot. Read full article here: https://www.replicaairguns.com/2011/12/29/crosman-nightstalker-field-test-review.html