Barrel unscrewed itself?

[Mich]

Morning guys,

Got a problem here I've never seen before. Due to head into town in the next week or so and can visit the smith but curious to see if anyone's come across it.

Have have an old - early 70's - Remington 700 that's been well used to say the least. The problem is this....

After having who knows how many hundred or thousands rounds through it I noticed the barrel had unscrewed a fraction of an inch from the action when brass started to look funny after being fired. Lucky I caught it when I did before it reached a more dangerous point.

The rifle hasn't been used for years, but has never had a problem. It was an old family rifle, I don't know 100% but I doubt the barrel has ever been removed.

Noticing the barrel I removed it, there is no unusual wear on the threads as far as I can see and for lack of a better option I can only assume at the moment it's being vibrated out over the course of a number of shots.

Any ideas?

[anthillinside]

Not I, sorry I can't help you there.
But if you can find out what it is ... Bottle it.
It's normally the other way round, something that hasn't move in 30+ years needs serious effort to undo it.
I know a lot of people who would pay serious money to have something the releases stuck bolts like that

[bigfellascott]

switch barrel time!

[Spooner]

Maybe someone was an aspiring gunsmith who took a crack at it. Didn't quite get it back together.

[BBJ]

It's normally the other way round, something that hasn't move in 30+ years needs serious effort to undo it.

Mmm.

I can only guess someone has removed it and failed to reinsert it correctly at some point over the years.

Joins that old can be like trying to break apart a weld when you need to.

[Yelp]

That's a weird one.

Could you notice if it had unscrewed recently or ages ago? Was there a line of corrosion showing before and after or anything like that to give an indication of time when it came loose?

[trekin]

Morning guys,

Got a problem here I've never seen before. Due to head into town in the next week or so and can visit the smith but curious to see if anyone's come across it.

Have have an old - early 70's - Remington 700 that's been well used to say the least. The problem is this....

After having who knows how many hundred or thousands rounds through it I noticed the barrel had unscrewed a fraction of an inch from the action when brass started to look funny after being fired. Lucky I caught it when I did before it reached a more dangerous point.

The rifle hasn't been used for years, but has never had a problem. It was an old family rifle, I don't know 100% but I doubt the barrel has ever been removed.

Noticing the barrel I removed it, there is no unusual wear on the threads as far as I can see and for lack of a better option I can only assume at the moment it's being vibrated out over the course of a number of shots.

Any ideas?

Have seen the same thing once a long time ago. The cause then was a fracture running from the ejector port to the front of the action through the threads, that was invisible to the eye, but was detected using a Dye penetrant inspection method and confirmed with an Ultrasonic test. The problem was determined to be a combination of;
stress fractures originating from a contaminate in the steel used in the action, caused by the continued minute expansion and contraction of the barrel and action by the pressure generated when firing the cartridge. These fractures reduced the action's threads mechanical ability to lock the barrel threads in place.
the torquing of the barrel imparted by the projectile passing through the rifling.
This of course may not be the cause of your problem, but if you intend to kept using this rifle, and no obvious cause can be found, then it may pay to have your smith run a NDE (Nondestructive examination) on it for piece of mind.

[Jack V]

I was thinking the same thing either front action ring failure or someone did not fit it up properly with enough torque. Chances are it's the latter but a good inspection should be done to rule out any other reason . Also the cases would have been over stretched and will fail early .

[Westy]

Hey mitch if you keep shooting it ,who knows might screw it's self back up tight????LMFAO

[Jack V]

You would tend to think that it should tighten , right hand twist rate on right hand tenon thread but for some reason some get looser . Maybe it's recoil and vibration or maybe it's a bit of tight chambering and as the bolt closes it turns the loose barrel .

[Mich]

The cause then was a fracture running from the ejector port to the front of the action through the threads, that was invisible to the eye, but was detected using a Dye penetrant inspection method and confirmed with an Ultrasonic test.

Interesting. That's obviously something I can't do myself, will give the gunsmith a call and see if he has the equipment needed for that.

[Warrigul]

The cause then was a fracture running from the ejector port to the front of the action through the threads, that was invisible to the eye, but was detected using a Dye penetrant inspection method and confirmed with an Ultrasonic test.

Interesting. That's obviously something I can't do myself, will give the gunsmith a call and see if he has the equipment needed for that.

It isn't "rocket surgery"Your local welding shop may have the gear, either the dyes or magnetic induction with filings or Xray test gear. I have a test pack tucked away in my shed even though I don't use it anymore. I have tested a few old actions and never found a crack.

[brett1868]

Hey mitch if you keep shooting it ,who knows might screw it's self back up tight????LMFAO

Don't be silly Westy, he needs to load up some left handed rounds to do that

[Mich]

It isn't "rocket surgery"Your local welding shop may have the gear, either the dyes or magnetic induction with filings or Xray test gear. I have a test pack tucked away in my shed even though I don't use it anymore. I have tested a few old actions and never found a crack.

I just don't have the equipment myself. If the gunsmith doesn't have the geat I'll try others like a welder.

[kurl]

Don't be silly Westy, he needs to load up some left handed rounds to do that

Good luck, I'm still trying to find a left handed screwdriver and no one stocks them!