If your barrel is stainless try a tornado brush. Lewis lead removers work pretty well (if they still make them) and something called Lead-Away dissolves it but will also attack your bluing.
Sounds like your bullet lube or bullet diameter needs work. Gas checks could work if you like pushing lead fast
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Smokeless powder is a passing fad! -Steve Garbe
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My favorite recipes start out with a handful of used wheelweights.