Maybe one day, I'll buy an sniper varient of the mosin. I can tell you that you will notice the recoil. Any of the eastern block countries have produced the 7.62x54 for their militaries, so these ammos are easily available online. I brought two cases of czech which is about 1600 rounds total for about $360 from Aim Surplus.com.
You just have to try a box of different manufactorers to see which works best with the particular mosin before buying a case of em.
If you want to learn more about the Mosin rifles or any other military surplus weapons, then I suggest visiting Gunboards.com. You will find the CZ board there as well.
I thank you very much.