New Model 70 Cocking Cam Problems

Discussion in 'Gunsmithing' started by Another Casual, Apr 2, 2015.

  1. Another Casual

    Another Casual Member

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    I am somewhat at a loss with a stainless model 70 that I purchased last year.
    Not too long after owning it I noticed that the bolt was becoming harder to operate, to the point where it felt very raspy and needed noticeably more effort to work. I field stripped the bolt and noticed that the cocking piece had cut a groove up the entire length of the cocking cam on the bolt body (deep enough that it could be measured with the depth gauge on a set of dial calipers). I sent the gun into Winchester and the bolt came back polished. Not too long later I noticed that the groove was being cut again, so back it went. This time it came back with a new bolt (good on them) and I just field stripped the gun and it is growing another groove. I am completely at a loss on what to do with this firearm. I have tried multiple lubricants (just ordered another one), and am at the point where I am at my wit's end.

    Is this normal behavior? My only other two Mauser type actions (98 and CZ 527) are both designed so that the cocking piece contacts the full width of the cam, but the model 70 (both bolts) only contacts some of the cam.

    How do you keep your cocking cam area smooth and lubricated?
    Is it a stainless steel is harder thing and I should try to order a blued/matte cocking piece?

    I emailed Tubb's to see if their speed lock piece was softer or had a larger bearing surface and they said no.

    Am I just crazy? I've paid much less for guns that are much smoother. Mind you, I'm not necessarily talking about the effort needed to cock the gun with regards to spring pressure but to the general rough feel.

    Here is a picture before I sent the gun back for the second time (kuddos to them for paying shipping this time). Its hard to get a photograph that shows what's happening:
    [​IMG]

    Any advice or guidance or words of reason would be greatly appreciated.
    Thank you.
     
  2. EddieHarren

    EddieHarren Well-Known Member

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    A little grease, in the right places, works wonders.
     
  3. MagnumManiac

    MagnumManiac Well-Known Member

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    What does the cocking piece surface look like?
    If there is a corresponding wear pattern or groove cut in the cocking piece, then the 2 pieces have not been heat treated correctly, this is evidence of galling.
    I would polish both surfaces to see which wears quicker and address the softer ones hardness problem.

    Cheers.
    gun)
     
  4. Another Casual

    Another Casual Member

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    The galling was one of my first ideas, but I was unsure once the second bolt starting doing it as I figured the odds of two not being heat treated right would be low. The cocking piece itself does not really show any signs of wear. It only contacts the cam at its tip, not the entire length like it does on a Mauser 98. Can anyone recommend someone to re-heat treat the cocking cam area?


    With regards to grease, I've tried the factory lubricant, silicone based lubricants and I just ordered some "tetra grease" off amazon for a couple of bucks.
     
  5. MagnumManiac

    MagnumManiac Well-Known Member

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    I must add that any 2 metals riding against each other will show wear, which is not the same as galling, but, if it is only wear marks then you don't beed to worry about it, but if it is in fact a groove, it needs to be repaired.
    I cannot help with the heat treatment, unfortunately.

    Cheers.
    gun)
     
  6. Greyfox

    Greyfox Well-Known Member

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    Tagging on. Curious as to what's going on. I have never experienced this with my Model 70's
     
  7. Another Casual

    Another Casual Member

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    It is in fact a groove in the bolt body. You can easily catch your finger nail in it. I have some new gun grease on it which has made it feel smoother than the factory stuff, but I have no way to tell if it is not making the groove anymore. Very perplexed by this one.

    When you say "repaired", what do you suggest and who could so the work?


    My CZ 527 has a pin that rides through the shroud at the read of the bolt that then rides in two cocking cams, one on each side. That system is very very smooth.
     
  8. phorwath

    phorwath Well-Known Member

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    Winchester should want to figure this out and correct it before sending more rifles off to retail market. They agree there's a problem or they wouldn't be warranty working on it in the first place.

    If there's a groove wearing into the bolt body, and Winchester can't correct this, then bad on them. How many times have you cycled the bolt? I'd sell the gun if Winchester can't/won't fix it, unless you can ID the problem and come up with an easy fix. The steel in the bolt body is too soft, and/or the area of contact is too small to prevent metal removal at the location of the two mating surfaces during the rotation of the bolt.

    You'll incur a substantial cost for melonite treatment or any other heat treatment, and you won't have any assurance that your efforts and money spent would resolve the problem. Who knows better how to fix this than Winchester?

    If it's basically a plain-Jane factory rifle, and Winchester can't/won't fix it, I'd sell it and move on.
     
  9. Another Casual

    Another Casual Member

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    The temptation to sell it and move on is certainly there, but at the same time this is supposed to be a quality model and in all other aspects it is. Selling it would also mean taking a financial hit on the rifle as I had purchased it new. It seems like taking a hit through no fault of my own is kind of a bad shake. I am leery to send it back to Winchester again as they have been unsuccessful twice now in solving the issue. The fact that the new bolt they sent me is cutting the same groove is worrisome.

    Does anyone else have one of the new model 70's and have you experienced this? Specifically the stainless model.
     
  10. MagnumManiac

    MagnumManiac Well-Known Member

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    I have several, none of mine show the same groove.
    Is it possible that they sent you a bolt body only, not the firing pin assembly?
    I have both New Haven made classic stainless models and the new FN made stainless rifles, never seen this on any of them. I use moly lube on my bolts, inside and on ALL moving parts, this may help.

    I would be contacting Winchester again over this matter.

    Cheers.
    lightbulb
     
  11. Another Casual

    Another Casual Member

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    I de-greased the bolt today and took a few more pictures. Mind you this is the new bolt and has not been fired at all. All it has had is me working the bolt to check function/smoothness. Aka, not very much.

    [​IMG]

    [​IMG]

    [​IMG]

    Also, I sent Winchester an email with the pictures attatched and a description of the problem. I will keep you updated on that front. Thank you all for the suggestions and pushing me to email them again. I'd rather not take a monetary loss on this one.
     
  12. Ridgerunner665

    Ridgerunner665 Well-Known Member

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    Pics of the cocking piece... The part that is making that groove in the bolt body.
     
  13. Another Casual

    Another Casual Member

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    I just took pictures of the firing pin side of the equation for you. It doesn't look like there is any wear on that end to me, but I will let you all come to your own conclusions.

    [​IMG]

    [​IMG]

    When the pin is in the bolt body it is clear that the two angles are not the same. On my old mauser the firing pin and cocking cam parts are cut so that the full surface of each contacts the other. On both bolts for this rifle it only contacts the cam with the very tip of the firing pin.
     
  14. phorwath

    phorwath Well-Known Member

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    Looks like a POS bolt to me. Winchester should be embarrassed.