So here's the impacted ball... the zinc cleaner tail at bottom.
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The object impacted by the head of the ball, appears to be the brass part of a British Enfield pattern bore tompion, kept in the muzzle to keep out wet, mud, etc., as if, as was previously mentioned, the ball was fired while the tompion was in place. Some images of the tompion parts. The threaded end with the nut is the top of the tompion. The wider brass part, which in the present case is impacted by the lead of the ball, is the bottom of the tompion.
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