I found that pure lead allowed my herring wire inserts to wiggle loose. Also had some wire keepers wiggle loose too. Hopefully the link to the lead I posted earlier will prevent this. Just started using it a week ago and haven't got to test it on the water yet.

I don’t ever have cavities not fill completely but on every mold I use I insert the nozzle of my pot inside each cavity gate when pouring. I no longer just pour lead across the top of the mold. When I use to do it this way I would have incomplete heads at times, mainly heads with wire inserts, weed guards, etc. and Jacobs barbed molds.