As nearly as you can recall, were those 4 or 5 from VA? The absence of copper plugs in so many suggests they were used with wooden plugs. Augusta's records show them cast at the start of 1864. If they were not issued until April or May, the arsenals had been ordered to switch back to the old wooden field fuzes by then. I've seen some threaded VA shells that appear to have been fired with wood fuzes.
W.H.
