I'm gonna pop my head up for a minute now.
Friend, the ONLY way to get TOP accuracy from your Moisin-Nagant is to handload for it. When the military ammo hits the shops, it generally is old machine-gun stuff that had a LOT of dispersion built into it when it was made..... 40 or 50 years ago. It is 'surplus' for a REASON. Remember, Russia and several other countries are still using this as their sniping and medium machine-gun ammo, so they aren't disposing of it because they don't need it any more. They are disposing of it because they don't WANT it... and they can get us to pay evil Yankee $$$ for the privilege of taking their garbage off their hands.
With handloading, YOU are in control of the ammunition-manufacturing process and you can tailor a load which will work wonders in YOUR rifle.
That, and a bit of careful work on the bedding, woodwork and trigger and you can make an old MN 91/30 shoot well enough that you are going to WANT a scope. When that day comes, re-read what louthepou said about a scope mount. Lou is bang-on as usual. You can add a most UNsatisfactory mount to a stock MN for a lot of dollars. For LESS dollars, actually, you can put on an S&K mount and a LER scope which is 10 times BETTER and HALF the price of the ones 20 years ago.
For historical accuracy, the MN should be shot with the bayonet ON. That's what they were factory-sighted to do, with a 150-grain bullet.
And there is always what you were asking about: a more-or-less genuine MN sniper rifle, done up exactly the way that Vassily Zaitsev's rifle was done. The optics might LOOK funny from our perspective but they DO work and they ARE clear and, for the purposes they were designed for, they ARE worthwhile. MANY of these were done on the 'high-wall' receiver: left-hand rail was higher and more solid than the standard rail, affording a better mounting surface for the scope base. Others were done on standard frames. The guys in this forum KNOW what they are talking about; most of them WILL give you good advice.
As for Bubba, I'll give you one tiny example that you might appreciate. I picked up a Moisin-Nagant that Bubba had got his hands on. It was a FINNISH Dragoon rifle with a new PEACETIME inter-war barrel on it. It was about a $500 rifle when it started, but I got it for 50 bucks because it was beyond repair. I repaired it, with its own wood. Shoots real nice, too. But it is still only a $250 gun. That's why everybody detests Bubba.
You're having fun with your old MN now. Check out what the local clubs are doing. Around here, we have regular matches for old military rifles and they are fun. Some guys even turn out for Running Deer and other fairly-precision shoots with old military rifles and shoot against the modern stuff. It is quite amazing just how well these old-timers can score.
And, by the way, you will ALWAYS get better accuracy from a 91/30 with a .311 or even a .312 bullet. I have several that really like their Hornady 150 SPs.
And, whatever you do: have fun!
Okay, guys, I'm back in the trench; you can let fly any time now!