[Ben Cartwright SASS]

I was checking out a Mosin Nagant m44 carbine and my usual check is to put a 7.62x54R round in the muzzle end and see how much of the bullet doesn't go in, crude but effective.
I noticed right away that the first inch or so of the bore seems to be, how do I say it, turned down or drilled out or something, then there is a sharp ridge and the rifling starts right there.
I have never looked at a carbine before is this normal?

The cartridge goes in right to the neck.