Cast pellets from soldering tin?

Why not cast pellets from wheel weights? There must be tons of the things in old junk yards. The newer wheel weights are made of different material, but there are still lots of old wheels around.
As a car mechanic I had access to nearly unlimited amounts of old wheel weights. Wheel weights are what's called hard lead. It's basically garbage. Wheel weights, like pellets are lead alloyed with antimony and tin. Unfortunately wheel weights use a lot less lead than pellets and have a bunch of impurities that make it difficult to flow into complex and tight mold crevices. You'll get lots of voids and you'll probably have to remelt and recast half or more of what you cast. Each time.
Cheap fishermen including myself have tried using wheel weights for decades to cast simple shaped lures and sinkers. Like me, they usually give up when they realize how much more work it takes to cast still poor quality lures and sinkers. You can try smelting the lead to separate the alloys but it requires the very high temperatures that make lead dangerous.

Hard lead wheel weights are cheap but IMO aren't worth using because of the additional headaches. If you want cheap lead get permission to sift thru the sand burms at a gun range, melt it down and skim off the copper jackets and organic impurities. This still requires precautions to prevent dangerous lead exposure.
 
That's interesting... but if tin is harder, can it damage or at least wear off the barrel quickly than lead?

And what about dirt and coating? I am tempted to make a mold from kids clay and pour soldering tin inside to cast a few experimental pellets, but I don't want to ruin or dirt my barrels.
Tin is harder than lead. Steel is harder than tin. The tin shouldn't wear out the steel. It may require brushing out occasionally. I don't use tin pellets. They'll be someone here that does that knows the answer.

Kids clay will melt and you'll have molten metal and clay floating off the table. That's very dangerous