I use musket caps when I'm lighting off large (130-200grs.) black powder charges in my .69 and .72 round ball hunting rifles. I have a few British style .451 target rifles that came from the factory with musket nipples but converted them back to #11. No need for them in those rifles as I'm only burning 70-90 grains of black powder. If I used any substitute powder like pyrodex or Triple 7 i would use the musket cap to ensure instant ignition because of the higher ignition temperatures.
