1871 Swiss Vetterli

I have an 1871 Swiss Vetterli chambered in .41 Swiss. I am in process to convert it to centerfire and get the brass, bullets, etc to reload my own rounds and such. The immediate issue involves the chamber. I have some original .41 swiss rimfire rounds, they are the shotgun rounds, much like a .44 magnum shot round. These rounds were designed to fit this rifle.
The problem is the round will only go in so far. In the pics I uploaded it shows an original .41 swiss round in the chamber. The other pics show the empty chamber. on each side of the chamber as well as the top, you will see a small cut out. The ones on the side are where the firing pin fits in its forward position upon firing. The firing pin is double forked so that each side of a rimfire cartridge is impacted. It was designed that way in to prevent a misfire which is common with rimfire rounds. The cutout at the top of the chamber entrance is where the extractor fits when the bolt is closed.
Anyway, as you can see from the pics, the round will not go in any further. Let me know if you have any ideas to consider and I will respond accordingly.

Thanks in advance.

TC

You have some serious peening at the point of contact for the firing pins,would affect the ability of the rifle to chamber any round.Would suggest taking a medium grit india oilstone(round profile,a 1/4 " diameter would work well) and bringing the burr down. If this does not allow the round to chamber,make a Cerrosafe casting of the chamber and throat to determine what other action may be necessary.