A cannon's friction primer does have a wire, but it is a much shorter and smaller wire than what's in Mtholen's photos. (Also, one end of a friction primer's wire is serrated ...and the wire's body is multi-twisted, quite tightly -- see the photo, below.)
I do not recognize Mtholen's wires as being artillery related. There's none like them shown in any diagrams in civil war era artillery manuals. Also, I don't recognize them as any kind (or part of) a civil war Military relic.
Since I can't see "obvious" rust showing on them in the photos, I assume the wires are not made of iron. If so, are they copper wire, or are they brass wire?
What they remind me of is pieces of cut-up wire fence. But that can't be right if they're not iron wire.