Basically your friend is firing a 3 dram load with 9 pieces of buckshot, close to the same load used in police riot guns, but with the shot strung together. You didn't tell us the caliber of the gun, or gauge of the smoothbore. The load is not dangerous to the shooter as you describe, as the gun will handle it, and has. He will be leading the barrel unless that leather piece surrounds the 9 balls completely, to protect them from scraping against the barrel as they are fired. As for self defense, If you are going to use a shotgun to shoot someone, say a home invader, or someone trying to kill you, the fact that you make up this kind of load will probably be a factor in whether you get sued civilly, but it should make not difference to any possible criminal charges filed against you. A 20 or 12 ga. load of buckshot is recognized as being fatal at short ranges you find inside businesses and homes, and the fact that you tied the shot together does not make them more deadly. ( How dead is dead?) There are a certain lower order of humanity who hold law licenses who will seize on any variation from the norm to file a lawsuit, just to see if they can " get lucky" with a judge and jury, so using this kind of thing may guarantee you get sued. Your friend might want to think of that before making these loads up for his self defense guns.
When I was a kid, we had a fatal shooting on Christmas Eve at a local liquor store. The dead man had robbed and beaten the owner of the store almost to death the year before, and the owner was hospitalized for months recuperating. He was still not moving to well and had begun the practice is sitting in a rocking chair at the back of the store watching TV, while being able to look down a long narrow hall and see the front door if anyone came in. He keep a double barrel 12 ga. shotgun loaded, and leaning against the wall next to his rocker. The day in question, the bell on the door alerted him to the fact that someone was entering the store. The man had the same mask on that he had worn the year before, and was holding a revolver that looked like the one he had used to beat the owner senseless. Not seeing any clerk up front, the bandit came around the counter and started down the long hall. The owner had his 12 ga pointed at him, and told him to get out. The kept coming the owner gave him both barrels. There were pellets in both walls of that hallway, and the bandit died without saying a word. It turned out he had a regular job, was married and had two children, and lived only about 4 blocks from the liquor store. He was not known as a drinker. No one knows why he was pulling stickups. They shoveled and mopping a lot of him up off that hallway floor. A very sad gift for his Children's Christmas. Other than taking a statement, not another word was said to the owner, and no charges were ever even contemplated by the Prosecutor.
Another time, I guess.
