David W: Maybe somebody could post up a CLEAR description of what you mean, with illustrations, on the rig page then? Does sinking rig tube not hold any air? Even short lengths will surely trap some air, and thus float off the bottom. Mono loops around all over the place, and braid tangles too easily. I have complete confidence in leadcore.
What I described earlier will very easily pass over a knot and loop at the top of the rig. That was the point in my mentioning it. In fact it actually functions better all round than a loose bead, which I hold with a piece of soluble foam whan casting. I wouldn't use or recommend anything I thought might be unsafe for the fish. The other factor is to use line that's strong enough for the circumstances. I've NEVER lost a leadcore rig - I use either 17lb or 15lb line with it. If I was fishing over rocks or known sharp snags I wouldn't use it, nor would I use any other braids. I accept there is a residual risk - but there always is!
Perhaps somebody could come up with a leadcore or similar with mono running THROUGH it, somewhat like the tube, which I don't believe could be relied on to sink.
Having said all that, I retain an open mind. If I'm shown a better idea I WILL use it. I certainly have no objection to ESP, (I make up my own leadcore leaders), Korda or any other company making money from angling. It all helps to protect fishing from the depredations of PETA and the like.