Originally Posted by JonM
not just any barrel will work. it has to have the correct diameter at the chamber end to fit in the receiver and the correct type of threads with the correct thread pitch to match the receiver
You would be far better off just to buy the type of rifle you are trying to build.
If you completed your proposed project you would have a $600.00+, obsolete bolt action rifle worth about $100.00, maybe less after the alterations.
Someone was recently selling surplus machinegun heavy barrels for just such projects. It may have been Sarco or Numerich. If I remember right, they were threaded and chambered right for the Mosin-Nagant. Even with the barrel you need a lot of skilled labor to make it into a workable firearm.