What can I expect with one of these? I grabbed a Sako option standard condition. I actually prefer the patina look so less bluing is less important to me. It seems the barrels and internals are top notch with easily cleaned rust spots and some storage wear.

Are they covered with cosmo? Anything else I should know about the M39? Thanks!

You can expect a really nice milsurp rifle with better than average accuracy.  I am not familiar with them ever coming packed in grease, from anywhere, but I could be wrong, did you get your's from Classic Arms?

They have a barrel, stock, trigger and sights far superior to the Russians.  Careful if you take them out of the stock.  The Finn's space the actions with thin metal shims.  Once my shims got out of alignment, accuracy went south.  When I restored them to proper position, accuracy came back to normal and has stayed that way.

Sometimes they can shoot pretty high at 100 or 200.  I actually ordered a high front sight post designed to address that issue, brought point of impact down at 100 - 300 where I like it.  Not sure they are all that way.

Here is a pic of my Sako ordered from Empire Arms in 2007, along with a normal target at 200 yd from prone position (no sling).  I think the ammo was Bulgarian 180 gr yellow tip from 1955, fantastic ammo and perfectly preserved in those crude metal spam cans.  I don't shoot the rifle for groups very often, I have too much fun ringing the gongs.  Post here when yours comes in.

As long as the rifling is good, it should be one heck of a shooter.
Personally I prefer the ones that show use. The arsenal new ones are nice to look at, but just don't seem to be the best shooters. I guess that once the rifles hit the units they got tweaked for better accuracy. My favorite M39 has less than 25% blue and the stock has been nailed together in 3 places. Looks like hell but damn does it shoot!
Here's a pic of her, the little yellow spot right below the rear of the receiver is the head of one of the nails, and the faint line right below that is one of the cracks.

Thanks guys! Beautiful rifles by the way! Yes from Classic and they were very pleasant. Great advice about taking the stock off and the shims. I probably would have done that first and screwed the gun up.

Clearly in the Finnish culture and tradition shooting accuracy is a virtue, and in their military tactics and terrain an advantage over simply massed firepower.  Hence they developed a more accurate version of a rifle cost effectively available in their world, via purchase and via acquisition by warfare.  

In combat apparently the majority of Finn soldiers were armed with the M91s, however they did modify them for better accuracy including shims.  Not all Finn rifles have shims, but many of all types do.  Mine did and if you have one that shoots well, and you can avoid taking it out of the stock, that would be my recommendation.

Used rifles with dinged up stocks have character and may well have seen combat.  Mine came unissued and at the time there were a large number of unissued or excellent rifles available.   Some people believe like Dean did at DGR (well known gun restorer and seller of M1 Garands), "life's too short to shoot an ugly gun".  I like that philosophy, but also I'll take any rifle that shoots well.

I have a lot of fun shooting it, and have never attempted reload development or optimization of load for accuracy.  Now since 7.62x54R is no longer dirt cheap or surplus plentiful, that may be my next project.  The various Finn rifles will shoot various diameter bullets (.308, .310. .311 etc), and people recommend slugging the bore for reloading accuracy.  I doubt I will need to resort to that to find a bullet and accurate load in my M39.

Here is a great link if you haven't found it yet, plenty of great information here, the Finnish area of the Mosin Nagant web site, Mosin Nagant Site, and another good one, 7.62x54R Site, the M39 area of the 7.62x54R web site.

Thank you sir, I'll check it out!

You can expect one of the most fascinating rifles in 20th century history. You can expect a 19th century battle rifle reworked into one of the finest combat pieces of its era. You can expect a piece of art.

Get one, you wont regret it

It feels and looks like what a standard mosin should have been

The two stage trigger and sights are surprisingly good

That's right, the trigger is really great, truly rewarding to shoot a rifle designed for riflemen.

I have a Valmet (VKT) that I bought ten years ago, and a Sako from Classic's first batch. Both are fantastic shooters, and the Valmet is probably the most accurate rifle I own.