Hm. 33 days later and ... crickets?!
I'm gonna take that as a "no."
FWIW, MC, I clicked "watch" for your post, hoping someone with experience would chime in.
It would be an easier proposition of there was such a thing as lead wire; it'd be a lot easier than pounding and then trying to cut pieces reasonably close in size. That got me to thinking: why not use copper wire?
One might salvage cutoffs from electrical work, strip the insulation, then snip it into lengths roughly equivalent to the diameter. Copper would be soft enough to not damage a steel bore (there's lots of solid copper projectile chices out there). Given so much less mass, it might not carry much energy very far. But it would be an interesting experiment.