Making a comparison to a Temperature Gun reading should be used as a basic comparison only. A temperature gun only measures surface temperature, and does not measure internal temperature. Surface temperature will always be cooler than the coolant inside the engine. A common temperature difference would be between 5 and 25 degrees, between the water temperature gauge and a temperature gun. This depends on the efficiency of the component being shot with the temperature gun to dissipate heat. So, if your gauge reads 195 and you point & shoot and get a reading of 185, you can safely assume that you are seeing a reasonable, and realistic comparison. Only use a temperature gun to make basic temperature comparisons. Understand, that when everything is working correctly, the gauge will usually read higher since the gauge measures core temperature, and the temperature gun measures surface temperature.