Steve,
There were two long guns that we refered as Belgian Rifles. One was a .69 smooth bore that ususally fired buck and ball. One large ball and three small ones that were ususally somewhere between .31 and .36.
The other one was what we might call a Lorenz but it was made in Leige Belgium. THe early ones were .54 and some of them were bored out to .58 I think. These Lorenz's were sometimes refered to as Belgian Rifles also.
Early in the conflict, the COnfederate Govt. bought a lot of the .69's and as you might know, they also bought a lot of the Lorenz's.
So, I would think it depends on when they had these weapons. Early or later on.
FC