First some facts:
By regulation all cb radios max output can be no more than 4W. Some do illegal modifications to get more. It's illegal. Others do peaks and tunes. These often do more harm than good to a radio.
Second the most important check of the radio is SWR. Internal meters are not often goo and only tell if you have a bad issue. A $20 meter usually could measure SWR and power output. SWR needs to be less than 2. The closer to 1. The better. Check SWR in an open area like a mall parking lot away from the building.
Third is distance is limited by line of sight. Buildings, Forrest, mountains, and large metal objects inhibit the signal. Many conversations you hear during the day are SKIP. This is when the signal bounces off the stratosphere. It isn't controlled and your receive isn't limited to what signal it receives. I could hear conversations a state or two away at times.
So having said this what is your SWR on 1, 19, and 40?
Find more facts on firestick tech website.