Here is some more info from Cortland


"All fly lines are rated at 30'.


Example: A DT-6-F. WF-6-S and a WF-6 F, at 30', weigh the same.

When you have 15' of fly line out the tip of the rod, using a WF-6 line, you only are casting approx. a 3 wt. line.

AFTMA Fly Line Standards

Weight Size (grains) Tolerance AFTMA (the former American Fishing Tackle Manufacturers Association- now the ASA- American Sportfishing Association) Fly Line Standards were developed to help fly fishing tackle manufacturers create a system that would match fly line weight to fly rod performance. Cortland Line Company’s Leon Chandler was instrumental in initiating and completing the project. In theory this would standardize fly tackle manufacturing across the industry and enable fly fishers to select and balance their equipment for optimum performance.

The system uses the weight in grains (a very small weight measure) of the first 30 feet of fly line as a standard. The table below shows fly line weight designations and their grain weight. The system also established a tolerance level that is acceptable.

CORTLAND LINE COMPANY ADHERES TO AFTMA STANDARDS!

Beware of over-weighted lines that give you a false sense of fly line and rod performance.

1 60 54-66
2 80 74-86
3 100 94-106
4 120 114-126
5 140 134-146
6 160 152-168
7 185 177-193
8 210 202-218
9 240 230-250
10 280 270-290
11 330 318-342
12 380 368-392

Courtesy of Cortland Line Co.

Sinking lines


Density of sinking lines are measure in rate/second in inches.

Sinking lines and floating line - of the same line rating - weigh the same.

TYPE CHARACTER SINK RATE (inch/second)
1 slow (intermediate) 1 1/4 - 1 3/4 ips
2 fast 2 1/2 - 3 ips
3 extra fast 3 1/2 - 4 ips
4 super sinker 4 1/4 - 5 ips
5 super fast 5 1/4 - 6 ips
6 extra super sinker 6 1/4 - 7 ips

Courtesy Cortland line Co.

Shooting heads.


These lines are generally 30' in length. They can be of various constructions, Floating, Sinking, Floating with a sink tip, Measured in Grains for sinking rates.