I have changed my leader to ring connection for jigging to a series of 15 reversed half hitches. Straight line pull testing with AG Liu convinced me this was a better connection when my uni snapped 10 of 10 times & Liu didn't even re-tie his half hitch knot. I do incorporate a chafe 'tube' consisting of some hollow material over the leader where it contacts the ring.
As Mal suggests, perhaps the knot failure is really due to abraision of the swivel/ring? Having said that, I previously used uni knots without any additional chafe protection and never had one fail, I suspect due to the rings I use being oval and very thick, much thicker than 9mm hyperwire rings, thus perhaps less of a cutting tendancy?
Andrew
after having the uni knot break several times last year I added a lumo thimble like what you have on gamefishing leaders. what do you know........ no more breakages and still the same batch of mono.
