What's the bore diameter?

[Bowhunter57]

I'd like to purchase a Finnish Mosin-Nagant M-39, but I'd like to know the bore diameter. I understand that some of the Russian Mosin-Nagant rifles are .311 bore, but the Finnish models were rebarreled and their bore diameter is .308.

I'd prefer to purchase a .308 bore diameter, if possible. Is there a standard bore diameter for these rifles?

Your opinions and experience is appreciated.
Thank you, Bowhunter57

[savageT]

BowHunter,
Starrett Tools makes a device for machinists......it's a split sphere internal caliper that expands to fill a hole.  It has a rod running through the center of the sphere to expand/contract to fit the bore.  Then, you measure the caliper diameter with micrometers or dial caliper to determine the bore diameter.  If you are at a gunshow or shop, preset the split ball internal caliper for 0.308" and try it in the unknown barrels.  You now have a go/nogo gauge.  Now, other than going to a machinists supply store to purchase said caliper (or actually a set of these in a little pouch), you might be able to sweet-talk a machinist or gunsmith to let you borrow one? My thoughts also included using a new drill-bit, but there aren't any that are available in those diameters, sorry......
Jim
P.S.  You can also slug the bore with a lead sinker.

[Rick Teal]

It's my understanding that the "Bore" size of a 7.62X54 is .300 as it is named (7.62 converts to .300).  The Soviets, however, cut their rifling deeper than was the normal case in North America and Western Europe.

I believe the spec. was that the barrels had a land to land (bullet) diameter of about .3108.  

During the wars, manufacturing standards for the Mosin Nagant rifles often varied from plant to plant.  I understand that actual bores varied in their land to land diameters between .309 and .313 with .311 to .312 being the most common range.  I've heard that .308 bullets will shoot well in Mosins that have smaller land to land diameter bores, but I'm unaware of any rebarreling programs.  I understood that the Finns just took captured Soviet firearms and used them to arm their own troops - however, I may be misinformed.

My suggestion would be to simply choose a rifle that has a good quality bore, slug it, and shoot the appropriate bullet diameter.

[kevin.303]

i made a post on the handloading forum about relaoding the 7.62x54R. some of the answers i got go very in depth explaining the bore diameter on the varoius M/N's. that might give you an answer.

[S.S.]

.310 - .314 is a good average range for Mosin Bores.
The Finns did re-barrel a huge number of captured Nagants
with a barrel of considerably larger outside diameter.
Heavy barrel I guess you could call it.
Many of these barrels also had a Chrome lined bore.
They added a different sight system and a different
stock design.  and fittings for a Blade Bayonet.
The Mosins that were re-worked by the
Finns took many shooting championships and a couple of world
records in their time! It has been said by many folks that
the Finnish Mosin model 27's and 28's were the most accurate
Bolt action military rifles ever produced. Many Eastern
European military sniper rifles and target rifles are still based on the Nagant!
" If it ain't broke don't fix it " I guess.

[1911crazy]

S.Sumner your right about the accuracy of the Finnish  Mosins  these guys were all marksmans and were known for making 600meter shots with just iron sites.                                                   BigBill