I thought that he asked a question about priming the pan, not a civil war musket that takes a musket cap that is always put on last before firing. how did your friend get a blast to the face loading a cap lock musket? if indeed it some how went off it should have only burnt his hand.
I only told the story to point out what a muzzle blast can do to a person.
A muzzle blast from a civil war musket and a revolutionary war musket will have the same effect.
That is one hazard a person exposes themselves to when priming the pan first.
It could be even more disastrous because of a ramrod and/or projectile in the bore if the powder is ever ignited.
Also please read my post again for a full understanding of what I was attempting to convey.