I would concur with the above comments, I would say that the AFTMA ratings were to give you the weight line for a basic fly line that that rod is rated for, having said that, I have experimented with a OPST Skagit line of 150 gr8 on my 3 weight and it casts beatifully, for clear water trout? No but for river and warm water what a line. I also nowadays go for a half or one size heavier on all but my 2 weight.