Quote Originally Posted by Jonezee
How many people actually weigh their fly lines? How many have a scale to weigh in grains? What if you shorten your line by a foot? It still works. My opinion, most manufactures are within 15 to 20% actual grain accuracy so there will be margin for error in most all fly lines.
I have a scale and weigh fly lines all the time. This is because I make all of the lines I use on my 2 handed rods. I can tell you that as little as 10 grains can make a difference in how a line casts. In my opinion 15 to 20% is a huge margin of error and I would hope the line manufactors are a lot closer then that.