The best replacement for lead core is steel core ammo.

The best alternatives to lead core are rated as following:
★★★★★  steel core ammo
★★★★  tubing
★★★★  copper line
★★★  dipsy diver
★★  wireline
★  snap weights
★  downrigger
★  steel core

Your alternative for lead core is not listed? Suggest!
Speaking about lead core, one probably shouldn't forget about planer boards.

Other search terms related to lead core and their ratings are:
★★★★★ planer boards
★★★ planer board
You have in mind a companion for lead core and it is not yet here? Propose!



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lead core
steel core ammo
tubing