Sometimes you have to actually use something for a while to really appreciate its strengths and/or shortcomings. The 7.62X54R is virtually a ballistic twin of the .30/06 and anything the '06 can do, the commie .30 can do equally well when fired from similar rifles. But there's the fly in the ointment. The 7.62X54R is never chambered in rifles that are commonly encountered in western markets, not that the cartridge isn't capable, but the case design is awkward for modern bolt actions to accommodate, whereas the more conventionally designed 7.62X39 and its offspring have developed a following in Western markets and are manufactured by at least a couple of Western arms manufacturers.
The Mosin Nagant rifle comes with so many built in limitations that it is little wonder no one has ever been tempted to bring out a custom sporter version, although the carbine version has sort of an appealing look that might tempt someone to try. The split bridge does not allow for convenient scope mounting, or a ghost ring for that matter. The trigger is poor, being long and creepy with what seems like a mile of over travel, no feel for sear engagement can be established, and as far as I know there is nothing in the aftermarket word that improves upon that. Then there's the stock. The stock truly makes you wonder what the Soviets had against their own soldiers, despite it's obvious suitability as a bludgeoning weapon. I challenge anyone to fire 10 rounds rapid fire out of the carbine, from prone at a 300 yard target, in weather warm enough that a T-shirt is the appropriate apparel, and tell me that they didn't loose focus long before they got the 10th round away. Perhaps the rifle version is heavy enough to mitigate the effect of that wicked curved steel butt plate but I'd sooner shoot 10 rounds prone from a .416 Rigby than try to hold the carbine for 10 without some artificial padding. I've never been described as a Weatherby fan, but compared to the Mosin Nagant, a MK-V in .300 Weatherby is a gift from the gods.