Rifle Bore Pitting

[GBExpat]

Questions about corroded bores on old milsurps (military surplus firearms) have long been a subject in forums like these.

I (probably many of us) have learned by experience that some of the ugliest bores will turn out to be decent shooters.

Years ago, after the K98ks (German WWII Mauser carbines) were getting hard to find at reasonable prices I responded to a Sarco(?) ad in ShotGunNews for "dark bore" $110 Yugo-refurb K98ks. I had a mirror-bore take-off K98k barrel that I was planning on using as a replacement. The Yugo-refurb arrived and that bore was fu-u-u-u-u-gy. So I cleaned it up ... and it looked little better.

I took it out back to quickly assure that there was no accuracy in the thing, and was shocked to find that it is still accurate enough for a walkabout field rifle.

So ... I ordered a 2nd Yugo. It arrived with a demil'd barrel (hole drilled in the side) and I was happy to install my spare barrel on that receiver.

 

[Scooter22]

As said try it first to see what the accuracy is like. If it isn,t good try counter boring it to clean it up to the good rifleing. Thats common with many milsurps and it works. Won,t make it a target rifle but I,ve seen a 6" group at 50 yds go to 2" or so. Good luck. As for old milsurps shooting well with sewer pipe bores they were made with very deep rifleing so they really grip the bullet even with what looks like a bad bore.

 

[Thehunta]

Thanks for the info very interesting stuff.

 

[BBBBill]

Which part about it would be make you want to part it?

Nothing in your case since it is a 760. As I said refinish when you have time (keep it oiled for now) and test the accuracy. If it don't shoot chop off the offending portion, re-crown, and try again. If it still don't shoot pick up a used barrel (or a new one if you can find it). It might take a while, but they do come up for sale occasionally. Just be sure to check/set headspace. Another option is counterboring or a pinned and welded or high temp silver soldered "bloop tube" to keep it legal length if the barrel won't clean up with at least 16+" of barrel.
The 740/742 (semi auto), on the other hand, is prone to beating the locking lugs to death, rendering the gun unusable. I've seen exactly one 742 out of 20+ in the last few years that had not beaten itself into submission. I would not waste 5 minutes on a 740/742. The pumps like yours seem to hold up pretty well in spite of the same method of bolt locking as the 740/742.
Ahlman's offers a 742 to pump conversion - https://ahlmans.com/remington-742-pump-conversion.html Perhaps they can advise which parts interchange between the guns. I would call them and ask if a 742 barrel might be usable if the gas port were plugged. There are two 742 barrels in 30-06 for sale on Gun Broker right now. A 270 for a 742 or a 760 might pop up at any time. You can build a search there for anything you want/need and get emails when something comes up.

 

[Jackrabbit1957]

Years ago I bought a 1910 Mexican mauser from an ad in Shotgun News. When it arrived I was sorely disappointed on first inspection as the bore looked as smooth as a baby's bottom. It sat in a corner for several weeks until I got ambition up to clean it, it cleaned up to fair with some pitting. Accuracy out to 600 yards is respectable. I gotta go along with shooting it and see what it does.

 

[BBBBill]

You might check with Nu Line Guns - http://www.nulineguns.com .I know that they've done some 742 to 760 conversions and would probably be able to tell what parts interchange or can be adapted. If the barrel won't shoot as is or after shortening/recrowning/counterboring that might be one of your few resources for parts and info.

 

[Thehunta]

Thank you sir

 

[Thehunta]

So got bigger issues, barrel is looking better after lots of work but shot twice more and it fires and then jams won’t eject round. Action works great until fired and in this picture I’m loading you can see after it’s fired the bolt comes back about an inch by itself during the shot therefore stuck in place and have to be rough with it to pump back the rest of the way to eject. Thoughts?

 

[SGW Gunsmith]

Most likely the tip of your bolt lock (part of the trigger assembly) is not contacting the rear of the action bars. Can you pull the trigger assembly out of the receiver (two pins) and then take a picture of the right side of the trigger assembly?

 

[Thehunta]

Yep I will upload today thank you

 

[Thehunta]

Most likely the tip of your bolt lock (part of the trigger assembly) is not contacting the rear of the action bars. Can you pull the trigger assembly out of the receiver (two pins) and then take a picture of the right side of the trigger assembly?

 

[SGW Gunsmith]

Trigger assembly all looks correct.

 

[Thehunta]

so what’s your next check on the list?

 

[SGW Gunsmith]

Next would be to make sure the extractor is still in the bolt face. Hard to diagnose without having the rifle on my bench.

 

[Thehunta]

I understand thank you tho

 

[Rex in OTZ]

I have a dark bore Mosin but strong rifleing, it shoots better than it has any right to.