Concerning bolt shroud gap/firing pin lug wear

Discussion in 'Sako Long/Magnum Actions' started by stickhunter, Aug 24, 2013.

  1. stickhunter

    stickhunter Member

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    Misako, after discovering the worn lug, I stopped holding the rifle up to dry fire --- it's perhaps deceiving how much energy is stored in mainspring, but when you have to recock a removed bolt, you realize how strong that spring really is! Glad you were OK.

    My firing ping has a hole in the cocking piece that looks to contain a pin, or more likely, a screw whose head has been drilled off (there is a conical depression). I wasn't relishing the idea of figuring out how to separate the pieces, since this seems like a commonly-asked, but never fully answered question. Fortunately, the replacement I ordered is the complete assembly.

    Also, for those who have been following this thread, my post from a couple of days ago with additional pictures has been approved (thanks, Misako!), so please check it out --- any thoughts on that apparent machining error? I think it may very well be the reason the lug was filed down...


    Here's a link back to the new message:
    http://www.sakocollectors.com/forum...ing-pin-lug-wear&p=40341&viewfull=1#post40341
     

  2. misako50

    misako50 Sako-addicted

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    Stick- my apologies for not taking care of the pictures sooner. I was always able to see those pictures and assumed we all were looking at the same thread information. I see you have found your shroud and cocking piece hard to dismantle. The older ones had tiny screws and the newer have plugs. I would let a gunsmith toy with it but not something that I would mess with. I hope you are someplace close to a good smith where you reside. I have always had a tendency to make friends out of the smiths I've used over the years. Getting late here so tomorrow is another day.-Misako
     
  3. gunner620

    gunner620 Well-Known Member

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    Stick, that is surely a problem !! I have never seen anything like it.I can't see it leaving the factory that way and also can't see how that much damage could happen by bolt operation. No wonder you were having heavy bolt lift and hard trigger pull. I agree that at this point that just the firing pin assembly may not be enough. Jim
     
  4. gunner620

    gunner620 Well-Known Member

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    Stick,I sent you a private message, look at notifications at the top of the page. Jim
     
  5. stickhunter

    stickhunter Member

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    Phew, I've been waiting a couple of weeks to post this update --- glad the site is back up and running, thanks to all!

    Just wanted to follow up with a conclusion (hopefully!) to this issue.

    I was able to source a new firing pin assembly from Stoeger. Their parts person said they only stock L61R firing pins, but that they are compatible with the AV action. The new assembly arrived and I measured the shroud lug width at 0.155" compared to 0.045" on my worn assembly -- check out the difference in the second picture!

    Everything went back together easily and the firing pin protrusion ended up within spec. So things look good. I'll be keeping the shroud lug lubricated with moly grease and checking it periodically to ensure no significant wear is occurring.

    Here's some pictures comparing the old assembly (above) to the new assembly (below). Notice that the new bolt shroud doesn't wrap around at the bottom to the sides of the cocking piece, the cocking piece profile is different, the spring is shorter, and the checkering is slightly coarser. Fortunately, function appears to be fine and there's no longer any gap between the bolt body and shroud when cocked.

    Just to be safe, I'm going to have a gunsmith check the headspace before I try out the rifle and verify that the L61R firing pin is truly compatible.

    [​IMG]
    [​IMG][​IMG]
    [​IMG]

    And best of all, the shroud has no gap when cocked and no play when uncocked:

    [​IMG]

    Thanks for everyone's input. Unless the new shroud starts showing wear, I guess it'll remain a mystery how/why the old shroud ended up the way it did. I was pleasantly surprised that I was only out $100 to fix this problem --- knock on wood!
     
    Last edited: Oct 2, 2013

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