Hi Michael,
I risk being asking the obvious, or having negleted some of the 'lectures' you already have posted, so forgive me for asking you now the folowing:
1 - Were breech chamber locking bars allways made of iron, or were some other times of wood?
2 - Were chambers allways only loaded with gunpowder, or were they some times loaded also with the projectile?
Sorry for my ignorance

.
Fernando