Are you talking about the 7.62X54R Russian round. If you are NO. It is a critter all it's own. Lapua makes cases for this round but it is called 7.62X53R. It is the same case as the 54R but to get around the non military chambering laws in their country they shortened the neck to 53. Prvi Partizan makes ammo for this round and had good cases. I use them all the time. The best load I have found for this round in the Mosin Nagant bolt rifles consist of 50 grs Accurate 4350, CCI 200 primer, .311 diameter 174 gr Sierra Match King or 180 gr Sierra SP, OAL 3.000 If your rifle needs .312 bullets then the Hornady .312 174 gr RNSP with OAL 2.790 is very accurate. This is important to the accuracy of this load. USE A LEE FACTORY CRIMP DIE ON IT.
You will need to slug the bore on these military rifles to see what diameter bullet you will need. If the slug comes out .310 to .3105 use .311 bullets if .3105 to .312 us .312 bullets. If it is over .312 get rid of it and find you another because it will not shoot accurately with jacketed bullets.
Don't be fooled by these old rifles. They will shoot. They look like crap but when properly tuned they will shoot extremely accurate.
