Mosin - odd barrel condition

[andrew375]

Just bought another Mosin, a 91 rifle, octagonal receiver, 1925 barrel date. I bought it on the strength of its overall condition with little sign of use. I even put my Olympus bore scope down the barrel and the throat and the rifling over the first few inches look like new. At the muzzle it looked like a severe case of leading though, that didn't put me off as I'd seen this many times from people using store bought, undersize bullets.

After an epic cleaning session, which only confirmed my suspicions of under-size cast bullets I put the bore scope down again and what I had thought was leading is still there! Basically the barrel looks like new until about 8 inches from the muzzle when the surface just breaks down looking like, if it were at the breech end, severe erosion. The surface is all smoothed out with little sign of rifling and is quite rough and pitted as if it had been heavily rusted and for some time. The change between the surface conditions is quite sudden, leading me to suspect the rifle had been stored muzzle down for quite some time, possibly partially submerged. There is no evidence of water damage or work to cover up water damage on the outside.

Has anyone else come across this? What could be the cause?

I've heard of Mosins being counter-bored in order to remove cleaning rod damage, but this isn't a machined surface and pushing a tight patch through it does not feel as if the bore is any different in size. I've shot a few rounds with the Lee .312-185 (sized .3145") it seems to shoot ok though accuracy disappears rather fast if the bullet is pushed just a little too fast.

I am not to bothered if it is a dead loss as I decided to risk buying on the basis that it looks in exceptional condition otherwise, even the bolt feels like it is just off the production line, so that I will be able to sell it on with out losing money. It is just a shame all the barrel isn't in the same condition as the first two thirds. Usually it is the breech end that gets eroded away!

[Gtek]

Did I read you purchased a really nice carbine?

[leebuilder]

Hi Andrew I hazard to guess what happened to your 91. I can assume the leading covered a dirty corrosive bore and it rusted underneath, since there is no water damage. I had two 91/30s with trumpet muzzles. I cut them both down sporterized one and built a carbine like rifle out of the other, both are fine shooters now.

[Eddie2002]

Does a wet patch show any signs of copper fouling? I have a mosin that had some serious copper fouling, ended up soaking the bore with household ammonia for four or five hours then cleaning with a brush and Hoppes. Did 3 cycles of the soak/clean and ended up with a much better bore. It finally hits paper at 100 yds, couldn't hit a barn from the inside when I started. Almost sounds like you have crud buildup in the barrel.

[nicholst55]

Sounds like a candidate for 1) a chop job, 2) counterboring, or 3) a new barrel. I knew and old gunsmith who has worked on more rifles than I've even seen who recommended running a neck and throat reamer at least 1" down the muzzle of all milsurp rifles. He said that he did it as a matter of course, and they normally shot better after that treatment.

[andrew375]

Does a wet patch show any signs of copper fouling? I have a mosin that had some serious copper fouling, ended up soaking the bore with household ammonia for four or five hours then cleaning with a brush and Hoppes. Did 3 cycles of the soak/clean and ended up with a much better bore. It finally hits paper at 100 yds, couldn't hit a barn from the inside when I started. Almost sounds like you have crud buildup in the barrel.

Yes, there was considerable copper fouling, which I treated with several cycles of Ed's Red and Sweets 7.62. I am down to steel now. I wont be chopping the barrel, I should easily be able to sell it on just by the external condition alone. If necessary I can de-activate it and it will easily sell for what I paid for it.

[LAGS]

I had one like that.
I did several overnight soakings with Ammonia and cleaned it with a stainless bore brush.
Then several overnight soakings with Coke.
It came out a little frosted under the fouling but shot just fine.
Sold it to a friend and he polished it up some more with JB

[303Guy]

Did it look something like this?



This one still has some resemblance of rifling and does spin a boolit without stripping or leading but not very fast. I cut a piece off and fire-lapped it.