Assuming a full swing and a good impact, how much distance is gained or lost for each degree changed stronger or weaker?
Not a specific rule, as it can vary depending on the clubhead speed, angle of attack, etc. That being said, if you consider that the difference between clubs might be 10 – 15 yards, depending on the player, and there is 4 degrees difference between clubs, you might assume that a 1 degree change could effect distance by 2.5 to 3.75 yards. However, you have to remember that 1/2″ in club length will account for half of that distance difference beween clubs. So, just changing the loft by 1 degree, with no length variable, would only effect the distance by 1.25 yds. – 1.875 yds, generally speaking.