Re: Accuracy casting
I would say that you leader is the problem , the 6lb cant take the energy coming from a 40 ft cast. try a couple feet of 15lb then a 6lb tippet.
As for the issue of a longer leader I find that many store bought leaders butt section is too short and to thin. For instance when i fish with my 4wt using a 12 ft leader i use 5 feet of 20lb, then 2ft of 15lb 1 ft of 10lb 1 ft 8lb them my tippet (3ft). Hope this helps.