Recent Win M-70's with chronic problems

Discussion in 'Gunsmithing Forum' started by WillDgunny, Aug 20, 2011.

  1. WillDgunny

    WillDgunny New Member

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    New to this site, looking for advise and input from professional colegues.
    I'm a second generation gunsmith and graduate from Trinidad State. Have seen over the past few years of Win M70's in the WSM calibers with factory defects stemming from the production year of when Winchester stopped production. It appears that many of the last units were shoved out the door as "Parts Guns". I have one in particular that is a thorn in my side.

    Anybody here have any firsthand experience????
     
  2. john323

    john323 Member

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    Win 70

    What's the problem?
     

  3. stalkingbear

    stalkingbear Well-Known Member

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    I'd heard about that happening but didn't have any come to me personally before I retired.
     
  4. WillDgunny

    WillDgunny New Member

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    So far I have had three come through my shop. The first would not shoot anything less than a 3" moa reguardless of ammo, due to excessive tooling marks full length of the bore.

    The second had the mount screw holes so far off it was near impossible to mount anything up close to center.

    But the one that is still with me is a 300WSM that locks up after firing. Checking the chamber with my bore scope, I could clearly see that the chamber was clearly rough with reamer chatter marks. after checking the headspace, which is tight, I polished out the chamber and neck. I then rechecked the headspace which is now well within specs, but she stills locks up. Checking the fired brass reveal nothing and is within specs.
    Any Ideas??
     
  5. stalkingbear

    stalkingbear Well-Known Member

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    Do you have a finishing reamer for it? I'd try running it VERY carefully in just enough to clean up the chamber. Lacking that, polish the chamber. Make SURE you don't create excessive headspace.
     
  6. WillDgunny

    WillDgunny New Member

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    Yeah, may have to do just that, even if I have to step it back a thread.

    I'll jump back on it tommorrow and see what can be done.
     
  7. john323

    john323 Member

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    Sorry I misunderstood your post. I haven't had any show up in my shop.
     
  8. WillDgunny

    WillDgunny New Member

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    Well, as it is, this rifle still has me baffled. First round fires and extracts fine with out a hitch and the second round, you can't open the bolt even if you were to stand on it.

    Nobody else has ever had anything simular to occur to them?
     
  9. Duke5728

    Duke5728 New Member

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    I've never actually taken an M70 apart, but I just pored over some diagrams. Not to state the obvious (I'm just a novice so I don't know what's obvious to a trained professional or if I'm just being stupid) but it has to be the recoil knocking part of the bolt around. If the headspace wasn't the issue, consider what components may be coming out of place and sticking where they shouldn't be.
     
  10. Marlinman

    Marlinman New Member

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    Your locking lugs inside the reciever might be off a little bit. Me and my mentor had one in 270 wsm doing something similar. It turned out to be a burr on both the reciever and bolt. Same lug slot.

    God didnt make all men equal colonel Sam Colt did
     
  11. Belltactical

    Belltactical New Member

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    You could try lapping the bolt.
     
  12. Fisherking

    Fisherking New Member

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    Is the chamber concentric , totaly round . try takeing a few mesurments around the chamber or do a cast with creosafe and measure that.
    It could be the lugs too, but just an other avenue to look at.

    F.K.