There have been many-many ideas tried for firearms. Many of them worthless and/or dangerous. I was once shown a little known CW experimental 'bolt action' rifled musket muzzle loader repeater. Yes, weird. Several charge and ball loads were put in over the previous one and after a shot the 'bolt' would be worked bringing up another for a rapid follow-up shot. I don't think it worked very well. This rifle is in the safe of the Ralph Foster Museum at College of the Ozarks in Point Lookout, Missouri near Branson. I t is not on display, I was given a special showing.