I strongly suspect that no piece of case-shot matrix large enough to cause a wound would "survive" the shell's explosion... because all the versions of civil war case-shot shell matrix were (deliberately chosen) highly flammable material. Pitch, sulfur, and pine-resin matrix all burn with only a little encouragement. I think the flame-blast of a blackpowder explosion is plenty of encouragement... leaving nothing of the matrix which could cause a wound.
Regards,
Pete
Dec. 26, 2021 Note: I used the Edit option to clarify the first sentence above, because a typo and an accidentally-left-out word made its meaning unclear.