Model 70 Extreme Weather Headspace

S

Semisub

Inactive
This is a follow-up to a earlier post I made about a warranty replacement I received from Winchester/Browning and some questions I had concerning its milling. I actually took that rifle to a gunsmith who pointed out a bigger issue of the bolt face contacting the tenon of the barrel and that accuracy would suffer.

I sent the rifle back and requested that if it were to be replaced that they check for function and accuracy of the new rifle. A little less than a month later I received a replacement rifle. The serial number denotes it to be 10 rifles apart from the one I sent in. Unfortunately, the rifle exhibits the same exact issues as the last one and am not aware if the service center shot it for accuracy. Not sure if I'm making something of nothing or if this is a real issue. From what I have read, it seems that the headspace is not correct, but can't find specific examples of this with another model 70. I have attached a couple of pictures to show my concern. If anybody has any insight or suggestions, I'm all ears. I really like this rifle model, but for this price point, I feel it should be better and perhaps it's just a bad run. Not sure how to move forward.
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Have you shot the new rifle yet? How do you know it has headspace issues? I haven't read your other post, so I'm probably a little behind on the info.
 
I have not the shot the rifle, nor did I shoot the last one. Once the gunsmith alerted me to the issue, I contacted Winchester and they told me to send it in. I assume that they check the rifles over and test them, and if it there is a problem, they address it. So by them sending a replacement, I figured they saw it as a problem.

Is it normal for the bolt face to scrape the barrel tenon? I by no means am a gun expert, so I'm honestly asking.
 
What's the headspace now, if you know what it is.

Does the bolt face touch the barrel tenon forcing cone at that red mark when a GO headspace gauge is chambered? If not, all is good. Maybe grind a little bit off there.

I think those bolts can go far enough in on an empty chamber to rub the forcing cone.
 
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That I can't answer as I have not done so. I guess the next step is to buy some GO, NO GO gauges and check. I honestly just thought the bolt face shouldn't be contacting the barrel tenon at all, but that belief was instilled by the gunsmith I had look it over that builds precision rifles.
 
I think Bart s correct.

The headspace gauge or cartridge will limit how far the bolt goes forward,if they are in the chamber.

With nothing in the chamber,what surface would limit the bolt's forward travel?

Your smithmay have a point if that contact exists with a round or gauge in the chamber.
If the locking lugs in the receiver are fully in contact with with the locking lugs of the bolt,the bolt is in its rearmost position.

For the bolt to make the contact you see with the magic marker while the bolt is in full contact with the locking lugs,I believe you would have an interference situation.it would be difficult or impossible to close the bolt....unless you are setup with a clearance less than the thickness of a coat of marker ink. That's not easy to do.
 
For a competition shooter that may be the difference between winning and loosing. For hunting you don't need the added accuracy. What is your purpose for this rifle?

While contact may not be as accurate, it wouldn't be unsafe, as long as the headspace is correct. Get the go/no go gauges and check it. If the go fits, and the no go doesn't, then do the color test again with the go gauge installed. If the headspace is correct and there's still contact, shoot it and see what the accuracy is like. Try a few different types of ammo. Not all guns like the same bullet.
 
HiBC said:
I think Bart s correct.

The headspace gauge or cartridge will limit how far the bolt goes forward,if they are in the chamber.

With nothing in the chamber,what surface would limit the bolt's forward travel?

Your smithmay have a point if that contact exists with a round or gauge in the chamber.
If the locking lugs in the receiver are fully in contact with with the locking lugs of the bolt,the bolt is in its rearmost position.

For the bolt to make the contact you see with the magic marker while the bolt is in full contact with the locking lugs,I believe you would have an interference situation.it would be difficult or impossible to close the bolt....unless you are setup with a clearance less than the thickness of a coat of marker ink. That's not easy to do.
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Yes, it is interesting that the gunsmith didn't mention if it mattered if there was a round in it or not. He just closed the bolt and moved it back and forth with no play felt and stated the issue. Also interesting that Winchester replaced the rifle if they didn't see it as a problem.

I did cycle some dummy rounds and some of them proved difficult to close and open the bolt handle when going through a full magazine. I thought that could just be because it is a new rifle that is not broken in, but also wondered if it was due to the bolt barrel contact. There were also pretty good scratches on the brass, but that would be caused by something different obviously.

There was obvious scraping on the tenon of barrel before I used the marker to highlight the issue.
 
big al hunter said:
For a competition shooter that may be the difference between winning and loosing. For hunting you don't need the added accuracy. What is your purpose for this rifle?

While contact may not be as accurate, it wouldn't be unsafe, as long as the headspace is correct. Get the go/no go gauges and check it. If the go fits, and the no go doesn't, then do the color test again with the go gauge installed. If the headspace is correct and there's still contact, shoot it and see what the accuracy is like. Try a few different types of ammo. Not all guns like the same bullet.
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This will be setup as a hunting rifle, but we all like the best accuracy out of a gun no matter it's purpose. I definitely understand the difference you are stating though.

Yes, the ultimate question to be answered is how does it shoot. This all came about because the Extreme Weather I bought about two years ago, I could not get it group at all. I tried about 8 different factory offerings and a friend even attempted to make a handload to no avail. This, with making sure torque on action and optic mounting was correct and using a different optic as well. Winchester/Browning said they couldn't get it to shoot either after a recrown.

Who knows, maybe the gunsmith I visited saw an opportunity to try to sway me in having a custom rifle built, lol. I just took the issue he told me and sent it right back to Winchester without firing it. Again, weird that if they saw nothing wrong in their evaluation, that they would again send me a new replacement, even though that replacement exhibits the same signs as the previous rifle.

Thank you, @Bart B., @HiBC, and @big al hunter for your insight and suggestions! I will grab some headspace gauges and check the rifle before firing it. I'll report back with my findings.
 
I'm thinking that you should not send it back without shooting it. If it shoots well, then keep it. I don't think that there's anything in real life that is totally perfect to the millionth of an inch.
 
Try this: disassemble the bolt, very easy on a M70 with 3 position winged safety and with the stripped bolt in battery check to see if you can move the bolt back and forth. If it moves back and forth there is clearance. I doesn't need much. Keep in mind a single sheet of standard looseleaf paper is about .0035" thick... (3 and 1/2 thousandths)
 
From what I have read, it seems that the headspace is not correct
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You check headspace with a headspace gauge, not reading about it.
I have attached a couple of pictures to show my concern.
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If you are referring to the tooling marks and the forging flaws, just remember it is a mass-produced product and there will be imperfections that do not affect the performance of the rifle.
Have you shot the new rifle yet?
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This is exactly the question you should be asking yourself: if I haven't fired it yet, how do I know if there is a problem or not? Just like a scratch on a new car does not mean it's undriveable, a visual imperfection in an obscure area of a rifle does not make it unsafe or inaccurate.

I am a gunsmith by trade. I have customers who bring me brand new guns, never fired, and want me to do a safety inspection. I inspect them, maybe touch up a few things, deburr a few holes, but THE GUN IS BRAND NEW. If it fires, is acceptably accurate, and has no easily detected blemishes, use it. If it works as advertised, use it! If it doesn't, then call the factory. But you haven't even used the gun yet.
 
Some of the best advice I ever read was on savage shooters forum; if in doubt let someone else fire it, and if the shot is not followed by a loud scream you're good to go.;)
 
Semisub said:
This is a follow-up to a earlier post I made about a warranty replacement I received from Winchester/Browning and some questions I had concerning its milling. I actually took that rifle to a gunsmith who pointed out a bigger issue of the bolt face contacting the tenon of the barrel and that accuracy would suffer.

I sent the rifle back and requested that if it were to be replaced that they check for function and accuracy of the new rifle. A little less than a month later I received a replacement rifle. The serial number denotes it to be 10 rifles apart from the one I sent in. Unfortunately, the rifle exhibits the same exact issues as the last one and am not aware if the service center shot it for accuracy. Not sure if I'm making something of nothing or if this is a real issue. From what I have read, it seems that the headspace is not correct, but can't find specific examples of this with another model 70. I have attached a couple of pictures to show my concern. If anybody has any insight or suggestions, I'm all ears. I really like this rifle model, but for this price point, I feel it should be better and perhaps it's just a bad run. Not sure how to move forward.
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View attachment 111174
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I think you need a new gunsmith.
 
You have what is effectively a zero headspace rifle. That's one step to minimum brass stretch. It might end up a little ammo sensitive getting the bolt closed but I'll bet the chamber is as generous as any factory chamber tends to be so that probably won't be too big of an issue if it's one at all. All of my rifles run zero headspace. That means that with belted magnums I toss about 20% of my new brass for being out of spec and that for all my rifles, they can be a little touchy about case length from base to datum. All of my chambers are pretty snug too so between that and zero HS, my brass doesn't grow. I can just neck size and go for like 10 re-load cycles.

You needn't have sent that in to Winchester. You needed to have a gunsmith that had a small fine file on hand and wasn't afraid to use it. Shoot it before you pitch it. Actually, shoot the piss out of it before you even start having ideas that involve anything but shooting it.
 
Zero headspace? I know exactly what you meant. But wait and you may have a ear full from the Puritans on the forum. They did when I said the same years ago.

They want to hear the rifle has zero head clearance, or the headspace is 2.763" etc.

But they do sounds a bit less up tight lately, so you may get away from this transgression.

-TL

Sent from my SM-N960U using Tapatalk
 
The OP's concerns don't have anything to do with headspace. Zero,Zip,nada!.

If you stopped the chambering process .030 sooner ,or cut the chamber .030 deeper, it would have exactly zero effect on what our new rifle owner checked and observed. Its not headspace.

In fairness to his gunsmith,we are getting "What the gunsmith said" second hand. Before I condemn the gunsmith for being a phony hack,I need the explanation straight from the gunsmith.

The OP's observations come from some contact of the bolt lug corner to the cone feature of the barrel breech.

This can occur because the cone feature could be cut deeper. Cutting the cone deeper results in the brass having less support. There is a correct depth of the cone.

It can also occur because the corner break/radius on the bolt lug isn't quite enough. A little steel could be removed from the bolt where it is making contact.

It is also about the amount of bolt end play.

If the bolt is at its rear most position,as it would be during firing or a proper headspace check, There will be no contact at the point the OP is observing.

He is getting contact because the bolt is pushed forward,and the locking lugs are not in contact.

Basic mechanics,if two parts can slide past each othr freely,there is clearance. Zero clearance /zero interference is nearly impossible.

If the locking lugs are in full contact, the bolt making contact with the cone would be felt as interference.

To rotate the bolt into battery requires clearance..

If a cartridge or headspace gauge is holding the bolt to the rear,engaged with the locking lugs,there will be clearance at the breech cone a nd bolt.

A theoretical,and possible problem,that would degrade accuracy is the bore and bolt might not be co-axial. If the bolt approaches the chamber off-center,it might contact the cone.

At this point,I'd bet on it being much ado about nothing. The OP is suffering from illusions

OP,what if Winchester sent you a new rifle just giving you the benefit of the doubt? Taking good care of you?

I don't see a problem with the rifle. I do see that the OP does not have a clear idea of how it all works,he has doubts perhaps fed by a gunsmith whose motives are unknown.

Its all illusions.

Shoot the damn thing. And then realize even if your group does not meet your expectations,you might be a bad shot. You might not have ammo your rifle likes. A production M-70 barrel might not shoot to your expectations.

I think if the rifle groups 1 1/2 MOA or even 2 MOA,...you,or I might be a little disappointed.but the rifle is doing all we have any right to expect.from a production hunting rifle.

Not every off the rack commercial rifle shoots 3/4 MOA or less (except for on the Internet)
 
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The last Clymer reamer I ordered, I was asked if I wanted a Winchester throat or a standard throat. Of course I asked what Winchester throat, ah like no throat. So apparently Winchester decided putting a tapered throat into a barrel was a waste of time. Would not surprise me to find that they decided to go to minimum headspace also.
 
Regarding some of the terminology used herein, consider this.

According to the industry standards in SAAMI terms, chamber freebore is the diameter and length from chamber mouth to where the throat starts. The chamber throat starts at the freebore front then tapers down to bore diameter.

Some cartridge SAAMI spec chambers have no freebore and the throat starts angling down at the chamber mouth.
 
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