Originally Posted by learning2fly
Not sure if your line has anything to do with it? Maybe its too obvious but weight forward makes a huge difference
With all due respect, you are mistaken. It is neither obvious or correct.
A standard WF line is exactly like the DT for the first 30 feet, plus a DT continues to have the thick body so it loads more mass than a WF line as the casts get longer. So the WF would actually load the rod less
with more line out.
As the CCS measurement showed, the problem is not that the 4 wt fly line over loads his rod on long cast, it is that he cannot get the rod to load. So the rod is way underlined.
The profile of a Cortland fly line is below
The only difference would be a specialty WF line like a bass bug WF line has an extremely short front taper like a bass bug taper. The Scientific Anglers bass bug taper below has a 3.0 ft front taper vs an 8.0 front taper for the standard Cortland WF fly line above.
According to the CCS measurement the rod is not even the 6 wt that is on the rod. Hence the need to borrow a 8/9 wt fly line to test the rod.