The last recorded use was during Seven Pines, Butler ordered two for $1300 as did Fremont and Lincoln when they were demonstrated to him ordered all 10 available. McClellan ordered 50, but if I recall correctly the order was cancelled due to overheating, misfiring, range issues and the expense of the required tubes.
There was a thread on these some time ago and if I recall correctly Ripley cancelled McClellan's order, I'll have to find my contracts book along with my Ripley tome. Home office is a wreck right now. I believe that to be the 96th PA with one on the right, in 1862.
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