Winchester 70 re-barrel

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toad29

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I’m finally getting around to a long awaited project and going to rebarrel a left hand Winchester 70 classic in 300 wsm to a 35 wsm/35 sambar. I was expecting it to be a 1”-28tpi thread on the barrel and receiver but when I actually got it apart it was the 1”-16tpi.
After thinking about it for a while I’m wondering if there’s any advantage in taking the receiver threads up to 1&1/16”-16 and then turning the barrel to match or just leave it 1x16. Has anyone else done this before or what’s another opinion on it
Thanks!
 
Absolutely. I would not re-barrel any WSM without re-threading the receiver to 1 1/16. The interrupted thread is a problem with the WSM chamberings. In fact, for myself, I re-thread all post-64 Model 70's.
 
Because, especially in the WSM chamberings, the chamber wall at the tenon is a bit thin. Not a problem if the thread is complete and fits well but problematic when the thread is interrupted as on the New Haven post-64's. When the barrel is torqued on, the chamber is distorted. This is why Winchester chose to change the thread size on the Model 70's. They did this first on the shortion action which were made for the WSSM cartridges. This change was made before the move to NC. Then all the Model 70's were changed over, regardless of chambering. In order to be double certain Winchester also changed the thread from 16 to 28 TPI.
It is a measly 1/16 inch but it is the difference between a thread that is complete and one which is interrupted. Others are welcome to use the receivers as they are but I will not. It's not that difficult.
 
There are a lot of gunsmiths out there who are unknown to me. I'm sure a lot are capable of doing quality work on a Model 70. I know Gary Flach is and so is Ralf Martini. Jon Kollenbrander in Cranbrook should be capable as well. If it was me looking to have a Model 70 worked on and didn't want to do it myself, I would give Gary a call.
 
It means the thread is incomplete. In the case of the New Haven, post-64, Model 70's, the locking lug raceways are broached right through the threads. This means that at 3 oclock and nine oclock, there is a gap, a bit over .4" wide, where there are no threads. The apearance is a lot like the threads used on many takedown rifles. In most cases, this is of no consequence but with the large diameter WSM cases, the chamber wall can be thin enough that the chamber is distorted when the barrel is tightened on.
 
Leeper said:
It means the thread is incomplete. In the case of the New Haven, post-64, Model 70's, the locking lug raceways are broached right through the threads. This means that at 3 oclock and nine oclock, there is a gap, a bit over .4" wide, where there are no threads. The apearance is a lot like the threads used on many takedown rifles. In most cases, this is of no consequence but with the large diameter WSM cases, the chamber wall can be thin enough that the chamber is distorted when the barrel is tightened on.
Click to expand...

Possibly that lack of thread support would come into effect as well under full pressure of firing?
 
It is possible. Many early WSM rifles produced oval cases but I can't say for sure how much was the result of chamber pressure. I do know, on one rifle, I could improve the situation by simply reducing the torque on the barrel. Not an elegant solution and, in the end, I rethreaded the receiver and sleeved the barrel tenon.
 
Leeper said:
It means the thread is incomplete. In the case of the New Haven, post-64, Model 70's, the locking lug raceways are broached right through the threads. This means that at 3 oclock and nine oclock, there is a gap, a bit over .4" wide, where there are no threads. The apearance is a lot like the threads used on many takedown rifles. In most cases, this is of no consequence but with the large diameter WSM cases, the chamber wall can be thin enough that the chamber is distorted when the barrel is tightened on.
Click to expand...

Further to this Looky, an interrupted thread is used a lot by heavy artillery manufacture's that don't use the "Krupp sliding bolt design". Google most any artillery over 105 MM and photos will be easy to find of the "breach plug" with an interrupted thread...basically it allows the breach to be slammed shut in the "no thread position" and then given a 1/4 or so turn to lock the treads that haven't been removed during manuf. and then fired.

a good example available for a tabletop look-see is the mag tube in a takedown model of a 97 Win. pump shotgun. give the mag tube the required turn and slide it out of the frame as if you were going to do a complete take-down. the treads you now can see on the mag tube are a form of "interrupted threads".
 
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