Bryndon,
Sent a PM.
Bertram No.2 brass is available from many sellers.
Looks to be a wonderful rifle.
My 1869 is Henry rifled. I would suspect that there are a fair number of sporters and target rifles with either type of rifling.
I guess that was down to personal preference in the day.
Were there any other choices? Did Enfield rifling come in with the advent of the 303?