How I set up my semi-fixed carp rigs onto leadcore. The semi-fixed set up works by initially giving a bolt effect when a carp takes the bait. After a certain amount of force the lead ring will snap off the nodules and freely slide up the mainline.
I organize my leadcore leaders by using a fast change system.
You can push the ring passed the nodules on the rubber, this helps to hold the lead in place up to a certain amount of resistance, after which the rig acts like a running rig.