Just a heads up regarding replica matchlocks made for the reenactor market..
I have recently acquired one of these which I intend to use for lecturing purposes. It looked like it was .75" calibre, so I was going to try it using a Brown Bess load.
On cleaning the gun i discovered that the breech is sleeved for about 6" of the breech face using .45 tubing. The gun has been UKproved for blank and shot, and this design is apparently meant to stop ball being used..
I think this is a rather dangerous design as it is not obvious and if you did try to load ball, i suspect you might burst the barrel! There is no legal requirement to do this, so I am somewhat at a loss as to the logic.
Be careful if you come across one of these beasts of UK origin..