There is little to no collector's value to most Russian made Mosin-Nagants. I suggest going to mosinnagant.net for detailed information. The older the rifle the more 'value'. Study the design changes and that will help you decide. Those made before WW1 are extremely rare and have sight measurements marked in Arshins (converted to meters in 1924).

If you can find one made in the US then it's rare too.
http://en.wikipedia.org/wiki/Mosin

The Finnish versions are the most accurate and are worth about $300.

Standard Russian versions will almost always shoot high, sometimes as much as 6 inches at 100 yards. Check for good bores and undamaged muzzles. The short versions are said to have noticable muzzle flash. You will want all accessories including dog collars and bayonet.

My first choice would be a model 28/76 made by the finn's from the model 28/30 with the hex barrel. But that would be a far cry to find. The later years of 1940/43 model 91/30, B barrel models are exceptional were Tikki and are also very common finds. They are excellent shooters. No matter what some would have you think. The Nagant was an excellent firearm. Look up some fats as stated above. There is a U-Tube on a 1000 yard mosin nagant somewhere posted

Again 28/76, 28/30 Hexigon barrels Finnish versions Tikki versions. The true sniper versions after 1940 were excellant rifles m28/43 m28/44.But they are rare. the 28/76's will cost you $600 for well used but even at that they are worth the money.An excellent condition will cost you duoble that. They will appreciate in value over time.And are suberb shooters.

I have not shot the carbine version but this is what I've read:

1) The muzzle blast / flash / sound is very noticable and to some people uncomfortable.

2) Being lighter, the carbine will have a more noticable recoil

3) The carbine's sights were adjusted for a deployed bayonet. Thus, you will shift the point of bullet impact if you fold back or remove the bayonet.