For the reloaders who are interested in shooting this rifle, there is a thread going on Facebook about it. GSC has developed a series of dedicated bullets with this cartridge in mind exclusively.
This variety of bore diameters has been a problem with current bullets. GSC often makes bullets for double rifles where the two barrels are of different diameters through much shooting of one barrel, a single replacement or just the way it was made originally. One bullet can be used in both barrels now and, where a bolt rifle has a known/slugged size, we make bullets in a dedicated diameter for the barrel. We have drawn on this varying bore size technology to solve the problem with Mosin Nagant rifles as well. We make bullets for the reloaders who want to slug the bore and for those who do not, we have alternative bullets that will work as well.