Headspace Issue on a Win Model 70 Belted Magnum

[mikegideon]

I took in a buddy's Winchester Model 70 because he was having a problem sighting it in. Long story short, that problem was due to a set of windage adjustable rings (cheesy ones at that) that required a good bore sighter to install. Once the gun was bore sighted, I took it over to Stones River so I could sight it in.

 

The gun hit real close to the center of the target at 25 yards on the first shot. As I was bumping it in, I noticed that it wouldn't extract a live round, but worked fine after it was fired. I probably should have stopped right there. Anyway, I finally looked at the fired brass. It was nickel plated, and had a bright ring right above the belt, maybe 1/16" wide. Looked like the case was stretching. The shoulder was being pushed as much as 1/8" or more. I didn't have any measuring tools.

 

The origin of the gun is unknown. I guess the first question should be... Who's the best gunsmith out there to headspace a Model 70? From what I've read, it involves a finish reamer. The gun lives in Murfreesboro.

 

Comments? What am I missing?

 

EDIT: Forgot to add... 7mm Remington Magnum

Edited November 24, 2013 by mikegideon

[gregintenn]

Less than minimum headspace requires a finish reamer. I would think you couldn't close the bolt on a live round were that the case. Excessive headspace requires cutting the shoulder of the barrel, extending the threads in order to install the barrel another turn, cutting the face of the chamber, and then possibly the finish reamer.

 

Was the bolt difficult to close on a live round? Is it a factory barrel? Could it possibly be faulty ammunition?

 

An easy check for excessive headspace would be to take a hole punch and cut two thicknesses of paper, and place them between the boltface and a round of ammunition. If the bolt will close on this arrangement, you have excessive headspace.

 

You do realize the 7mm mag headspaces on the belt, right?

Edited November 24, 2013 by gregintenn

[mikegideon]

It's excessive headspace. Yes, I'm aware that it spaces on the belt. Bolt closes just fine. Won't extract a live round, but will fire. It's a factory barrel. Not an ammo problem. It was this stuff...

 

Edited November 24, 2013 by mikegideon

[mikegideon]

Less than minimum headspace requires a finish reamer. I would think you couldn't close the bolt on a live round were that the case. Excessive headspace requires cutting the shoulder of the barrel, extending the threads in order to install the barrel another turn, cutting the face of the chamber, and then possibly the finish reamer.

 

Was the bolt difficult to close on a live round? Is it a factory barrel? Could it possibly be faulty ammunition?

 

An easy check for excessive headspace would be to take a hole punch and cut two thicknesses of paper, and place them between the boltface and a round of ammunition. If the bolt will close on this arrangement, you have excessive headspace.

 

You do realize the 7mm mag headspaces on the belt, right?

 

Yeah. I gathered the process went like that. Gonna take a real live gunsmith. At least the finish reamer is in stock at midway for 120 bucks. No way I would attempt anything like this, but it helps to know the tooling is available.

[gregintenn]

 

Won't extract a live round,

I can't wrap my head around why this happens. Is the Winchester a push feed model, or one with a claw extractor?

 

Anyway, the barrel will need to be set back a full turn to keep things lined up correctly and rechambered. You can do it with a lathe, or else it'll need to go to a gunsmith.

 

I wonder how it got in that condition.

 

Does it appear that the bolt lugs have set back into the receiver? If so, a steady diet of overpowered handloads may be the culprit.

 

Your average gunsmith should already have a finish reamer for a 7mm mag. If not, I'd likely go else ware.

Edited November 24, 2013 by gregintenn

[mikegideon]

I can't wrap my head around why this happens. Is the Winchester a push feed model, or one with a claw extractor?

 

Anyway, the barrel will need to be set back a full turn to keep things lined up correctly and rechambered. You can do it with a lathe, or else it'll need to go to a gunsmith.

 

I wonder how it got in that condition.

 

Does it appear that the bolt lugs have set back into the receiver? If so, a steady diet of overpowered handloads may be the culprit.

 

Your average gunsmith should already have a finish reamer for a 7mm mag. If not, I'd likely go else ware.

 

I can't either. Does the model 70 have matching serial numbers on the barrel and receiver? I'm certain that Bubba was involved somehow. Just don't know if it was a half assed barrel swap or what yet. I gave the gun back to my buddy, so I'm not able to look at it. It's a regular claw extractor (i think), with an ejector like an AR. Not familiar with push feed.

 

Do you know of a good smith? I don't know if it can survive Bubba again. :) I guess we're talking receiver replacement as a worst case. 

[gregintenn]

Unless it's a pre 64 model, or a family heirloom, it would be financially better to trade it off than to sink a bunch of money in it. They are common and aren't that expensive. I'm not sure any of mine have a serial number on the barrel.

 

In 1964, Winchester was bought out, and the new bean counters redesigned the model70 to a push feed design similar to a 700 Remington or model 10 Savage. (Think smooth bolt with no claw extractor). In the late 80's or early 90's, Winchester came out with the "Classic" action that resembled the pre 64 claw extractor action.

 

Sam Hoster in Gallatin would be my first thought. If the locking lugs are set back into the receiver, I believe I'd send it down the road.

[mikegideon]

Unless it's a pre 64 model, or a family heirloom, it would be financially better to trade it off than to sink a bunch of money in it. They are common and aren't that expensive. I'm not sure any of mine have a serial number on the barrel.

 

In 1964, Winchester was bought out, and the new bean counters redesigned the model70 to a push feed design similar to a 700 Remington or model 10 Savage. (Think smooth bolt with no claw extractor). In the late 80's or early 90's, Winchester came out with the "Classic" action that resembled the pre 64 claw extractor action.

 

Sam Hoster in Gallatin would be my first thought. If the locking lugs are set back into the receiver, I believe I'd send it down the road.

 

That's what I was thinking. I would think that it's worth having a smith declare it dead, and then trade it off with the dreaded salvage title. I think the gun is unsafe right now. Not good to just trade it off without full disclosure, even though that's probably what happened to my buddy.

[gregintenn]

That's what I was thinking. I would think that it's worth having a smith declare it dead, and then trade it off with the dreaded salvage title. I think the gun is unsafe right now. Not good to just trade it off without full disclosure, even though that's probably what happened to my buddy.

Right. There are some folks out there who'd love to buy it for parts or for a project, however.

Edited November 24, 2013 by gregintenn

[RED333]

64,000 dollar, will it load and extract a sized unloaded case?

I have a 7mm Rem Mag Browning X bolt.

I reload for it and have a few cases sized ready for loading.

[mikegideon]

64,000 dollar, will it load and extract a sized unloaded case?

I have a 7mm Rem Mag Browning X bolt.

I reload for it and have a few cases sized ready for loading.

 

I doubt it. Since it headspaces on the belt instead of the shoulder, headspace isn't really going to change. Naturally, it pushes back into the bolt face when the case blows out. But, a sized case should headspace the same as loaded ammo.

 

BTW: I have an X bolt in .243. My favorite bolt gun.

Edited November 24, 2013 by mikegideon

[gregintenn]

I'm not sure I understand how it'll chamber, but not extract a loaded case. With excessive headspace, I would expect a backed out primer in the fired case.

[mikegideon]

I'm not sure I understand how it'll chamber, but not extract a loaded case. With excessive headspace, I would expect a backed out primer in the fired case.

 

Don't know. Maybe it's reseating the primer. Lots of pressure there. No problem setting off the rounds either. I wish I would have hung onto a piece of loaded ammo and fired brass. Red can probably say how much shoulder movement you get, and if you can see any stretch marks right above the belt. Could just be a paranoid shooter (me) and a ganked up extractor.

 

A no go gauge would answer that question

Edited November 24, 2013 by mikegideon

[leroy]

Guys.... I think ya may be on to somethin RE: a "bubba barrel swap"; or it could be a bad resize on the case shoulder...

 

We used to shoot lots of 300 win mag... One of the things that happens sometimes with these belted mags is that in resizing; the shoulder is pushed back too far... The fact is that the belt is mostly on there for looks...It sounds ta me like the chamber cut for the belt is a bit sloppy; plus the shoulder is bein pushed back on the rounds... That's why the extractor wont pick up the round to "unload" prior ta firing...

 

We discovered (...the hard way naturally...) that a 300 really headspaces on the shoulder just like everything else without a belt... We tailored each round to each individual chamber (...we had two guns, a #1 V and a remington 40X single shot...)...  Before i did anything else; i would spend $30 or so dollars and buy a case gage from Brownell's and check a fired case... That should tell the story on the barrel / bolt headspace without doin too much; and you all can do it at home...

 

If this old gun is, indeed, a pre 64 winchester with a mauser (...claw...) extractor; the action is pretty valuable and the old gun probably ought to be salvaged... The action alone is worth a pretty good chunk of money... Remember, this thing is a standard length (...30-06...) sized action... Ya can make most anything ya want out of the action by just changin the barrel... I would recommend takin a good, hard look at all this and see if it is a shoulder set back problem with the loads... Ya get the "bright, shiney ring" thing when it is bad... I know, ive seen a pile of 'em; and probably have a few examples layin around the house...

 

Take a look and let us know what ya find...

 

leroy

[mikegideon]

'cept it's new premium grade ammo. Bad barrel install was my first thought. I'm kicking myself for not hanging onto some of that brass

Edited November 24, 2013 by mikegideon

[RED333]

Wonder if you push a round into the chamber with your finger and see just how far it goes?

[leroy]

Mike: RE: this....

'cept it's new premium grade ammo. Bad barrel install was my first thought. I'm kicking myself for not hanging onto some of that brass

Could be "tolerance stacking"... Long chamber ream plus too deep on the belt cut...   What we found was a pretty good difference in chambers between the two rifles that are both individually in spec... I wonder if any of your ole buddies has a case gage to check the factory ammo with?...

 

leroy

[gregintenn]

Mike: RE: this....

Could be "tolerance stacking"... Long chamber ream plus too deep on the belt cut...   What we found was a pretty good difference in chambers between the two rifles that are both individually in spec... I wonder if any of your ole buddies has a case gage to check the factory ammo with?...

 

leroy

Yeah, I'm still not convinced it's a headspace problem. Could be, but I'm not sure with the information provided. A bad box of ammo isn't exactly rare.

[mikegideon]

Mike: RE: this....

Could be "tolerance stacking"... Long chamber ream plus too deep on the belt cut...   What we found was a pretty good difference in chambers between the two rifles that are both individually in spec... I wonder if any of your ole buddies has a case gage to check the factory ammo with?...

 

leroy

 

Exactly what I'm thinking. I could have goobered up a case gauge if I didn't give all that brass back to him. I'm an idiot

[mikegideon]

Yeah, I'm still not convinced it's a headspace problem. Could be, but I'm not sure with the information provided. A bad box of ammo isn't exactly rare.

 

It's not a bad enough headspace problem that the firing pin won't reach the primer. Just need to measure everything.

[gregintenn]

I think a claw extractor would hold a round in place sufficiently to detonate a primer if the entire barrel was missing.

[mikegideon]

I think a claw extractor would hold a round in place sufficiently to detonate a primer if the entire barrel was missing.

 

I still can't figure out which extractor it was. Trying to work from memory. We tested the extractor with a piece of ammo. Again, it worked fine once the round had discharged.

 

EDIT: OK, I looked at some pics. It is a push feed.

Edited November 24, 2013 by mikegideon

[gregintenn]

Let's all get together and tear into it. :D

[mikegideon]

I'm pretty certain we could figure it out, especially with a no go gauge. I'm just thinking we don't have the tools. Leroy has the metal stuff down pat, given how he made his living all those years.