I know a few guys that make there own varmint bullets from .22lr brass, and they really go splat. There are sources for the lead wire to stuff in the brass. If you were a high volume varmint shooter, and had some spare time, I think this would be fun. I don't know the break even point, but some shoot several thousand rounds a year up in South Dakota and Wyoming. From what I have seen, they can be quite accurate. They are not match accurate, but plenty accurate for varmints.
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He is wanting to make "bullets", not brass.