Howdy
I have no idea what velocity a chain fired ball achieves, but I can tell you the recoil and the sound will get your attention. A bazzillion years ago, when I was young I was out in the woods and fields playing with my 44 cal brass framed 'Navy'. Yeah, I know, they were never made in 44 caliber.
Anyhoo, there was a wood chuck standing in a field, and I drew a bead on him. This was way back before Wonder Wads had been invented. The deal back then was to slobber Crisco over all the balls to prevent a chain fire. Let's not argue about where chain fires come from, the nipple end or the ball end. All I know is it was that woodchuck's lucky day. I pulled the trigger and the gun almost jumped out of my hand as the ball in the chamber next to the barrel came out too. I always assumed it hit the frame and then when who knows where. But the woodchuck lived to tell the tale.