My late brother actually did the same thing at the range 20 years ago. Not a proud moment for him, and he did find the splintered ramrod down range behind the target it hit nearly sideways and ripped mostly in two. I believe the rifle was an old TC Scout. Pretty cool old throw back syle muzzleloader, but a pain to clean.Few years ago I watched a guy shooting a muzzle loader at the range, he definitely has just got it and was trying to get ready for season opening a day or two later. He struggled to push the bullet down the bore and I was about to go talk to him after his next shot and tell him that a starter makes it easier than using his ram rod.
I got up and headed towards him just in time to see him rifle in sand bags about to fire and I see the end of his ramrod sticking out of the barrel . A bang and cloud of smoke and that ramrod was gone to parts unknown . He looked for it around the bench for a few minutes and I couldn't bring myself to tell him he just shot it down range. He figured it out and packed up shortly after