The 7.62x54R ammo for the Dragunov also is used in the Moison-Nagant bolt-action rifle. Both rifles will respond to high-quality commercially-loaded ammunition as offered by Sellers & Belloit, Lapua and others. Most of the Russian-made ammunition in this caliber and the 7.62x39 for the Ak and SKS is crap and should be avoided. I know the Moison-Nagant looks like it came out of a blacksmith shop but, with good ammo, it will surprise you. Friend of mine has one of the sniper rifles and this thing prints an inch and a half at 200 yards.
If one wants to get a truely accurate Mosin Nagant without guessing, get one of the Finns with a good bore. Either a model 27, 28, 28/30, or a 39. I have a Finnish Model 39, it is so accurate as to be spooky.
http://62x54r.net/MosinID/MosinM39.htm