You will have to contact the maker.
You will have to contact Steyr
1885 Mannlicher rifle
6.5 mm Mannlicher-Carcano Italian made rifle
The Mannlicher Model 85, in the year 1885.
50-500 USD depending on specifics
100-1500 USD depending on specifics
The Mannlicher-Carcano has a six round internal magazine.
I do not personally, but yes, there is a single shot rifle that can have the rifle barrel replaced with a shotgun barrel.
The barrel on a BSA Super Ten rifle is fit into place by screwing it into the receiver. It is tightened down until it fits snugly and then torqued to specifications to prevent movement.
Lee Harvey Oswald shot Kennedy with a Mannlicher-Carcano rifle.
That term refers to the outline shape of the outside of a rifle barrel.
the rifle, a mannlicher-carcano rifle, is in the US national archives.