Inaccurate Mosin -- where do I start?

[armoredman]

I have heard this one many many times - there was never a chrome lined bore on a Mosin. Chrome lining didn't hit vogue until the M16, and that was loooong after the Mosin's day. They were just taken care of when rearsenaled.
The Mosin is still one of the greatest deals around, and another poster was right - if it won't shoot straightm buy another just like it, and keep the first for parts...not that these rifles break that often, either.

 

[444]

The first thing I would do is slug the bore.
I own two.
The first one I got had a bore that measures .318"
At 500 yards shots would strike 10 YARDS on either side of the target.

"Chrome lining didn't hit vogue until the M16, and that was loooong after the Mosin's day. "
That isn't true of US arms.

 

[MilsurpShooter]

I just figured I'd throw out the thing about the cosmo because I've seen some of them that... Well it looks like a shape of the gun but you really wonder if a guns under it or if it has deteriorated away lol.

 

[The_Antibubba]

I was going to say what 444 said.

So I'll ask a few questions instead. What is counterboring and what does it do? And how would I be able to tell if it had been done to my rifle?

 

[lee n. field]

The first thing I would do is slug the bore.
I own two.
The first one I got had a bore that measures .318"
At 500 yards shots would strike 10 YARDS on either side of the target.

Are there special kits made for slugging a bore, or do you just hammer a bullet down the barrel with a dowel?

I don't have anything in a .30 lead bullet -- closest is .38.

 

[444]

Go to a store that sells fishing tackle: Wal-Mart as an example.
Get a package of egg sinkers. The ones that have a hole going clear through the center of the sinker from end to end.
Guess which one will provide a good fit for the bore.
The point of getting the ones with the hole for the line is so there is minimal spring back so it will give you a more accurate measurement.

 

[WayneConrad]

I think counterboring is a quick fix for a worn-out crown. The arsenal bores a hole in the muzzle, of a diameter much larger than the bore, an inch or two deep. Well, there's your recessed target crown, I guess.

If you try to slug a counterbored barrel, don't pick an egg that just fits in the end of the muzzle. When it hits the secret, hidden muzzle at the end of the counterbore, it will stick real good .

 

[lee n. field]

Go to a store that sells fishing tackle: Wal-Mart as an example.
Get a package of egg sinkers. The ones that have a hole going clear through the center of the sinker from end to end.
Guess which one will provide a good fit for the bore.
The point of getting the ones with the hole for the line is so there is minimal spring back so it will give you a more accurate measurement.

Good suggestion. I did that (hints -- don't bother with a wood dowel. Pick up a 1/4" brass rod to drive it through. If the sinker is slightly too small for the bore, a couple raps with a hammer will widen it out enough to get a decent impression.).

Should I be measuring lands or grooves? I measure .304 across lands, .314 across grooves.

 

[Cosmoline]

The first one I got had a bore that measures .318"

LOL It's the world's first 8x54JR