And in following Manny's advice, you will distort the heck out of your round ball, and do it differently with each shot. So much for shooting accuracy. If you cast your round balls, sort them by weight, and by appearance, take the time to load them down the barrel carefully, with the sprue up, why would you want to beat them flat by bounding a ramrod down the barrel on them, until the ramrod will bounce out of the gun?
Now there is a scientic procedure. How long is Manny's barrel? How long is yours? What caliber is yours? how much does your ramrod weigh, and whats it made of?
Instead, develop a good shooting( accurate) load off the bench, and if you are shooting a percussion rifle, it will shoot better if the powder is compressed. Use FFFg powder as it compresses much better than FFg. Use a chronograph to determine what pressure produces the most consistent velocities. Then mark your ramrod, and range rod to indicate when you have that compressed load each time, and "load to the mark".
Clean your barrel between shots, so that crud doesn't change the volume of your powder chamber so that you need more pressure to bring the load to the mark than when its clean. That will ruin your groups.
Manny has a lot of good advice, but IMHO, bouncing ramrods on pure lead balls isn't one of them.
Paul