The US started testing muti round ball loads with the black powder 45 Govt revolver in the late 1870's but nothing became an issued item. The 45-70
was also loaded with three (or four) round lead balls Remington still loaded these round ball loads during WW1 and they were used on guard duty
in remote areas with the old 1884 Springfield. I have a 30-40 Kragwith a muti ball load too. These have been around since the black powder days