I don't know if the .501 size would be a problem or not. The Hornady's I shoot are .512 for .50 cal. rifles. They have a wide spot toward the front that you have to push onto the rifling. Also the back of the bullet has a skirt like a mini-ball to expand and grip the bore. Would the .501 bullet just fall down the barrel? There is no skirt, would it upset enough to grip the rifling? Is there any way of getting a few in pure lead to try?
I am new at this, so these are probably dumb questions.