I just started using leadcore this year, so my way may not be the best, but this is what I got from surfing the web.
So, there I sat trying to figure out how to rig all this stuff up about a month ago. I found several references instructing to pinch the lead 6″ or so from the end of the line, leaving just the outer dacron sleeve with no lead for that last 6″. Then, most references recommended tying a swivel, then 10-20′ of your favorite mono or braid as a leader.
From there, I tied an improved clinch knot to a high-quality 30# berkley barrel swivel. To this, I tied ~10′ of 20# test fireline with a uni-knot. On the fireline end, I tied a dual locking snap.
With this set-up I have been able to catch fish trolling in the river. The snap lets me change baits easily and does not seem to affect action. The swivel prevents twist.
The biggest trick with this was pinching that lead and pulling it off that first 6″. Once you do that, the dacron is pliable and can be knotted. According to several articles I read, removing the lead does not affect strength. The # test is for the jacket, not the lead. Also, 27# leadcore supposedly does not sink any faster than 18#. I use 27#, it helps when Jimmy Hoffa is reachin’ up from the depths for a crankbait hor’d’oerve!
Regards,
Joe Jiacinto