do you think any of those $100 mosin nagant come with a good bore and muzzle?l got one it does not shoot straight at 100 yards...(the muzzle is counterbored)is it easy to replace the barrel with a good one? and finally I am looking to put a scope on the mosin nagant. The traditional way is too expensive but I've seen online you can replace the rear sight with a mount.. Has anyone actually done this? and does it work out ok?Thanks!

Some of the Nagants are brand new or arsenal refinished. It would be cheaper to sell yours and buy another than to replace the barrel.
As for the scope mounted on the rear sight it works. But you need a long eye relief scope IE a pistol scope.

give it a good bore cleaning .really good with an ammonia based bore solvent that will remove copper fouling.

Wall of truth.com has a nice tutorial on accurizing a the M/N rifle using a cork shim.

You dont give a lot of details on if your rifle groups or is high-low or stringing shots. hard to help without details

Man l am sorry to hear about ur bad bore, thankfully my M91/30 shoots excellent. I've had nothing but good experiences with it, & it has to suck having a lemon. l am not sure how good a $100 one will be, but l paid $150 for mine. It came with the bayonet, the sling, oil bottle, cleaning kit, & ammo pouches though too. Also l am sorry to say that I've never heard of anyone re-barreling a M91/30, l think they're cheap enough that most people just replace the whole rifle. Lastly, as to ur question of scoping a Mosin with a scout scope that replaces the rear sight..
Well l tried it, but l did not like it. First u will need a very long eye relief scope & 7x was about as high a magnification as l could find. Which really did not do anything for me. Also some of the mounts r aluminum & kind of cheap, so they tend to wobble which can make it hard to keep ur scope zeroed in.
l guess l prefer my Mil-surplus guns in their original configurations anyway, but it is ur rifle. If u want to scope it, l know cheaperthandirt.com, centerfiresystems.com, & midwayusa.com all sell various scope mounts for the Mosin Nagants.
l wish u luck, & l hope this helps.

If the barrel is bad then the gun itself is bad. Connot be replaced. Mosins r of varying quality. l have 3. Two 91/30 is one l use for hunting larger game as it is used but the bore is just a little frosted but shoots well. Another which at least hits what l am aiming at, not very well, & a m44 which has a very shiny bore but seems to have sticky bolt issues when it heats up. And that is with brass cased ammo.

The rear sight is a pain in the ass for any commie gun. l have tried once on an ak, that is enough l will never try again with the amount of crap that l had to go through (the new sight l was never able to install & now it just sits in the safe).

l have bought about ten 91/30 most had excellent bores & pretty fair accuracy
Sell ur & try again the odds r in ur favor
l never paid more than $75 for mine, the best was $39

As far as the scope mount goes
Those scout mounts may be cheaper but the price of a LER scope will eat up the difference very quickly

Sportsmans Guide had a fairly correct Belarus scope mount for $29
it should cost no more than $75 to have it installed, much cheaper if u can do it yourself with a good drill press & tap & die set

l have owned & shot quite a few 91/30s & very few that were counter-bored r ever good shooters, but then there is exceptions.

You have to understand why counter-boring actually is done. When the guns r brought into the arsenal for inspection, the ones that fail the muzzle gage check r candidates for this procedure. So, the barrel is either ''shot out'' from actual use or more likely, some soldier was not properly trained in cleaning the rifle (never from the muzzle!) & was over aggressive in the use of the cleaning rod wearing the muzzle shape.

The practice drills a hole larger than the muzzle for a couple inches down the bore. This is *supposed* to create a new muzzle crown of sorts down inside the barrel. Problem is it rarely works as intended, plus once this new internal crown is worn some, that is it for that barrel.

Changing barrels is out of the question, just buy another rifle & learn what to look for in the bore.

Yes, l have used a forward mount scope on a Mosin. l have my 'pig gun' set up on a carbine, complete with forward mount ''Scout Style'' scope. Of course, u need to use a pistol or LER/EER scope. Be aware this is very different from a traditional scope, but it has some unique advantages for short rifles used in heavy brush & only if the shooter is adaptable for this kind of low scope power both eyes open kind of hunting. BEWARE: most of the scout scope mounts sold for the Mosin r junk! Made cheaply & poorly designed. There r only two l would recommend & they r over $50.

Do not put a forward-scope on a 91/30. This is not a target shooting setup. Much better on a carbine.

The original side mounted scope mounts the Russians used on their snipers r readily available as r the scopes. l have a couple of the original complete Red Army sniper 91/30s. At around $400, it is expensive as Mosins go but cheaper than any other WWI l sniper rifle, & u r nearly guaranteed a fine shooting relic. (my Enfield cost 8 times that & is less accurate).

Here r some great articles u should read before even considering the Scout Mount. Also, l would highly recommend that u get a Mojo sight upgrade instead of a scope.