In re-reading my first post I can see I wasn't very clear and recognize how it could come across as whiney. Since the OP mentioned Mosins I'll share a little about mine:
I picked it up back when they were a dime-a-dozen but did my research. I found that the markings could be used as indicators (which factory and how the barrel was graded from the factory), but that the biggest limiting factor for distance accuracy was how centered the bore was in the barrel. I handled probably 30 or so before finding this one, with a smooth action (the bolt levers are notoriously ill-fitting after CZ got done with them) and reasonably centered barrel. I ditched the wood and got the cheap plastic monte carlo stock, but I hogged it out to free float the barrel. I also cut and welded a turn-down bolt lever and sanded down the trigger spring until it had a very light-but-still-crisp release. As it sits in that picture, I was consistently getting touch-groups at 300yds and 5" at 600yds. At 1000 I'd get 2 or 3 of 5 on 24" paper, (all with 203gr Silver Bear).
A real eye-opener for me was a 30* morning outside of Yakima right after sun up, I was able to see the vapor trail of the projectile in my scope, and I could literally see it corkscrew twice before wandering off in any direction. No idea what distances these events were happening, but it was still really cool to see.
Since that pic, I've removed the front sight, tapered the crown at 6* to a 1" depth and added a symetrical muzzle break. I've only had it out once since then though, at a 300yd range and it was nothing to brag about.
Oh, and the bipod is for tacti-cool dorky looks. I shoot off a bag when I shoot for real.