Without doubt, the most popular method of lead set ups in use in the UK at the moment is the lead release clip.
A lead release clip can also be used safely with leaders but, unlike the heli-rig, the leader will remain attached to the rig should a breakage occur.
The principal behind the release clip is that pressure from the front (hook end) of the rig will pull the clip free of the lead should it snag up on anything.
I personally prefer that the lead can detach with just a sharp jerk of the rig and submit my rigs to the same test as I use for the heli-rigs, if you can’t jar it off with a little flick then I am not happy with it!
A lot of carp anglers are paranoid that adjusting the clip so as it is more sensitive (safe) will mean lots of lost leads but remember that they can only detach when the rig is pulled from the hook end. Occasionally when the lead hits a shallow feature at speed it can ‘knock’ the lead free but it is a small price to pay for piece of mind, isn’t it?
On very weedy waters the clip can be trimmed back by cutting the arm back with scissors or just pushing the tail rubber lightly over the clip and, by using a heavy lead, it will discharge as soon as a fish hooks itself. After a fish looses the lead they tend to rise to the surface a lot quicker and it’s not unusual to strike and get an instant boil on the surface of the lake, even in fairly deep water.
When I’m carp fishing, the Zig rigs I use I take one step further and trim the clip back quite severely and, also, I only push the tail rubber up so that it actually sits just under the arm, rather than trapping the arm shut. With careful casting and a slow lowering of the lead to the bottom it will stay on the clip perfectly but, as soon as a fish takes the zig, the lead will fall off. I do this because playing fish on a long hook link where the lead could be left swing around six seven or even ten feet away from the carp can often lead to hook pulls.
For the lead to pull free of the clip; the clip must not be able to pull free of the rig swivel or else the whole lot, lead, clip and all; simply slides back up the line and can cause all sorts of problems during the fight, especially if weed is involved.
This is where the pin system on some lead clips comes in handy as it holds the clip in place on the swivel, I would never consider using a clip that didn’t actually fix to the swivel in one way or another.
Most lead clips are a plastic component and plastic will wear and tear in use, especially if you are catching a few fish or fishing at range with big leads. Keep an eye on the tail rubbers and replace them at the first sign of splitting at either end. A spilt at the pointed end will result in tangles as the hooklink will have something to catch on as it spins around the rubber. A split at the fat end of the tail rubber will seriously affect the pressure needed to release the lead and you may well start dropping leads on impact when you cast.
Also the arm that the lead is mounted on, in time, will weaken slightly and this should also be checked regularly, the clips are not overly expensive and you get ten in a packet so replace them as needed.
If your preference is for an in-line lead set up, which in reality is the most tangle free of all, then I would recommend removing the hard plastic insert and replacing it with a softer safety sleeve, these can be bought in packs of ten and are not overly expensive, they will add to the safety of the finished set-up. A lot of in-line leads are supplied with ‘hard’ plastic inners and most of these fail to pass my ‘bounce’ test for safety, I find the soft versions far safer. Obviously though, as with a helicopter set up, the in-line lead will always stay attached during the fight and, because of this, I wouldn’t recommend either in extremely weedy conditions as the lead can snag up and hinder the fight.