Frankly, I can think of no reason to fill a 12 Ga shell with dimes as lead BBs are cheap and work expremely well......

Historically at times of war folks took to doing wierd things to their ammunition because of severe shortages of commercial ammunition. I know a guy that claimed he cut the outside of the shotshell around almost totally where the bb level was so that when the shell was fired the entire foreward section of the shell went out the muzzle in one piece instead of ejecting the BBs only.....this was his way of simulating a slug when he couldn't get slugs.....He says it killed deer.....who knows.....but we can get almost anything we want today so why tempt fate with these type of experiments that might cause injury or damage the gun?????