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JamesK I think maybe I didn’t explain myself correctly ----or you mistook what I wrote.
Let me try again;
The headspace is the amount of space between the head of the shell and the bolt face. It’s measured differently from say, a rimmed shell than it is from a rimless shell in that it is going to be the measurement from that part of the chamber that stops the shells forward movement and the bolt face.
So on a rimmed shell it would be measured from the forward surface of the rim recess of the camber and the face of the bolt, and on a rimless shell (like the 8mm Mauser or a 30-06) it will be measured from the datum line of the shoulder to the face of the bolt.
With that said, throat erosion has NOTHING to do with headspace. The connection I was trying to make is simply that if someone has fired a 30-06 enough to need a new barrel it’s probably that such a gun would show itself to have excessive headspace in that amount of time just because every shell that is fired is going to stretch more than it should.
You’d never know if all you shot was factory ammo, but if you are hand loading the brass you’d be able to tell pretty fast. To shoot that much factory ammo would be very costly indeed.
Let me copy and paste my previous post again and see if it makes sense now in light of what I am trying to explain here.
However in rifles with excessive headspace your brass life is very short and it's unlikely that most men can fire a rifle enough to shoot out a throat with factory ammo unless they are quite wealthy. Also with that much shooting it usually becomes obvious to the rifles owner that the chamber is loose by examination of the fired brass.
But your point is valid.
Before such work is done the headspace should be checked and measured in the old barrel.
Now if you load many thousands of rounds and your brass life if 2-4 shots it’s likely you have a headspace problem.
If however your brass life is normal you probably have normal headspace and maybe even less than normal headspace.
So if the old barrel was checked for headspace (as it should be) and the new barrel was copied to those dimensions both outside and inside, you can (and I have --- more times than I can count) just screw in the new barrel and all will be well
None of this is to say that if you had a damaged receiver that this would fix it, but again I’d have to guess that if you have fired a 30-06 enough times to shoot out a barrel you’d probably know if these was something wrong with it by now.
Not…to address Oldgunsmith
I too am an old gunsmith
I’ve been doing this kind of work now since 1969.
I have been a full service gunsmith and at one time I did most of the gunsmithing for 7 shops in western Nevada, and I have also been doing work for a few here in Wyoming now for 15 years. I was the head ballistician for Cast Performance Bullet Company as well as a part owner for a few years, and then later the CEO of that company. I worked on guns from all over the world. I have been honored for my work by Safari Club International and also by the NMLRA (which has nothing to do with this kind of gunsmithing, but it’s enough to say I am not an amateur )
As far as “questioning the judgment” of doing this kind of thing, well, ---what do you think the barrel companies have done for many many years?
ER Shaw have been selling short AND LONG chamber barrels for so many years that they were “old timers” when I started gunsmithing back in 69
You buy a deep chambered barrel and use a lathe to set it back to proper headspace. Many other companies do the same thing. Most did this back in the 50s and 60s in fact.
These days it’s popular to do the opposite by selling short chambers and also a chamber reamer (makes more money that way)
Perhaps they believe that having the owner do his own headspacing is “safer” from lawyers and they may be correct, but if that’s the case it’s ONLY because they are trying to insulate themselves from lawyers.
It has nothing to do with gunsmithing per se.,
Kraigwy is 100% correct in his posts here. I also have made more barrels than I can count on rifles for target shooters. About 2” “too long” so they can have me set the barrel back as the throat shoot out. It’s a good way to do things, and keeps you from having to buy a new barrel every time.
He’s also right in that comment that truing the action is more important than lapping the lugs.
To set up an action to perfection with a new barrel it’s necessary to have them both, but not to simply rebarrel.
If you send in a Ruger, Winchester or Remington--- or about any gun to it’s manufacturer they will rebarrel them for you--- but they do not set the receivers up on mandrels and dial them in, and true them every time. It’s best, but it’s not necessary and it’s not dangerous to fail to do so.
As I said in my very 1st post “If the headspace is ok in the original barrel” you can proceed without having the action by simply sending the old barrel to a good gunsmith and having him copy it.
Nuff said
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