I've tried the sand method the sand needs to be slightly damp to hold the shape of the tube but not wet as said. I found it not very good as the sand is cold and the lead sets quickly and u end up with a hollow tube most of the time buy a 10 mm fishing ball lead mould cost me 10 or 15 quid if you want ovals give them a donk with a hammer or just use rebar cut at angles sharp as feck and quite heavy for its size