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K31 bolt question

Discussion in 'Rifle Country' started by Katitmail, Oct 30, 2014.

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  1. Katitmail

    Katitmail Member

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    I noticed that when I rack bolt without ammo (maybe same with ammo, didn't try it) - it's loaded but I can pull on a bolt and get a gap 1/8 inch between receiver and a bolt.

    Is that normal?
     

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  2. barnbwt

    barnbwt member

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    You don't actually pull on the bolt, you are pulling a handle that cams the bolt head rotation to unlock the action. The last 1/8" or so is when the unlocking occurs (as I recall) and the trigger becomes 'live' and can release the striker to hit the primer. It is a good idea to ensure the handle is fully forward (so the sleeve is fully rotated and the serial number on it visible) before pulling the trigger by firmly pushing the handle forward, but supposedly the striker more or less knocks the sleeve the rest of the way into battery as it falls, even if the action is slightly short of full forward (you are trusting in the mechanicals to do their job without breaking in that scenario, though)

    TCB
     
  3. barnbwt

    barnbwt member

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    Century should be beaten with an oar for their crimes...
     
  4. JohnnytheRipper

    JohnnytheRipper Member

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    I am not a gunsmith, but the K-31, if unmodified, should have a safety feature to force the gun into battery if the bolt doesn't fully lock. Either way, I tend to slam bolts home on any manual operation firearm, so it has never been a question of that.
     
  5. Guntoter

    Guntoter Member

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    Century should be beaten with an oar for their crimes...

    In some cases I tend to agree, in others, we wouldn't have many of the surplus guns we have if it weren't for Century. The real blame for that disfigurement lies on BATFE.

    From my understanding, the K-31 action is intended to be operated vigorously. Don't baby it. Yank it back and shove it forward. Unless the bolt is mis-matched it's unlikely you have a real problem. Mine seem to react the same as you describe.
     
  6. barnbwt

    barnbwt member

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    The other thing working against the K31 here is that the bolt head is not pretensioned; on a Steyr M95 straight pull, the bolt is forced into the closed position, making it impossible to short stroke the return. Obviously, this is at the expense of making the pull back much harder, so the user tends to work the "ruck-zuck" far more aggressively than the buttery-smooth K31.

    ...and Century stamped my K31 beneath the muzzle, unobtrusively. Unless the BATFE changed something for importers, Century simply went to a more press-accessible location to do the deed. "Waffinfabric Switzerland", whatever that's supposed to mean (Waffinfabric-what, exactly? Bern?) seems totally unnecessary, too, since the importer/location, model no., caliber, and serial are what is required last I read the statute

    TCB
     
  7. chicharrones

    chicharrones needs more ammo

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    Push that bolt all the way forward and go shoot that K31.

    EDIT - BTW, my K31 has that same gap with the bolt handle pulled back to that position.
     
    Last edited: Oct 30, 2014
  8. chicharrones

    chicharrones needs more ammo

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    Yeah, that's pretty blatant. Marking on the barrel is one thing, I've never seen marks from the importer on the top of the receiver like that before. :uhoh:

    Well, it's still a K31 and it is probably going to be a great shooter. :cool:
     
  9. Guntoter

    Guntoter Member

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    For a time, most importers were stamping the barrel and other unobtrusive areas. BATFE realized barrels could be easily changed and used Century as the 'example'.
    The BATFE clarification letters should be available somewhere on atf.gov. Century was cited for both size and location. They went to the extreme on size but all markings are required to be on the receiver now. It sucks but that's BATFE.
    Guntoter
     
  10. tark

    tark Member

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    I own a 1911 and a K-31. My experience with both is this: Ram that bolt with a lot of force in both directions, and you will be fine. Neither rifle likes to be handled gently.....
     
  11. zfk55

    zfk55 Member

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    Yeah! Great idea if you have a supply of op-rods. I'd say you've been lucky for quite a while, but that luck will round out on you if you treat that op-rod as you've described, Tark, and no Swiss rifle likes that sort of treatment.

    These two points on the lug, A&B are not inherently weak, but are the most common place for the Op-Rod to fail if its going to with repeated undue harsh use. Keep in mind the age of these rifles. Op-rod failure is the single most common problem for the older Swiss rifles.

    lug5.jpg


    We typically weld the LHO bridge to original Op-Rods, so we have intimate knowledge of the steel and its limits.
    (Thanks Guisan)


    We have Swiss Rifles here in the armoury, and I mean we have a lot of them, all kinds. When in correct mechanical condition not one of them requires undue force to cycle. Extraction is crisp and smooth, and running a correctly profiled cartridge into battery is smooth, effortless and a few at most requiring a solid push for the last 1/16" of bolt travel.

    If your bolt is clean and your cartridges properly sized, seat depth correct for the rifle you'll have no problem running a cartridge smoothly into battery. If you have to slap them in or out, you have a problem and one most likely easily solved.

    Rapping on the bolt handle with anything at all to remove a stuck case is a sure way to stress that op-rod and lug. Never, ever use a mallet or anything else on a k31 bolt handle.
    So how do you remove a stuck case in a Swiss Rifle?

    Try this:
    You need to apply strong rearward inertia to the entire bolt, not just the handle.

    Take the rifle in your left hand, holding it by the mid-foregrip. Place the edge your right hand (like a karate chop) against the bolt handle or you can grip it firmly with your fingers (not quite as effective with that type of bolt), or you can use a small block of wood in your hand to put downward pressure on the bolthandle. Raise the rifle about 18" off the ground and bring it down quickly, rapping the buttstock sharply against the ground while putting hard down pressure against the bolt with your right hand. Do it more than once if you need to, but I can tell you that its worked very time for me for as long as I've been reloading no matter what the rifle. If its a turn bolt action, rotate the bolt handle up and do the procedure. The AR10 is done the same way but just grip the bolt handle like you're extracting a cartridge and pull down hard while striking the butt on the ground.
    Don't do this on concrete for obvious reasons.

    *Not Latigo*

    Latigo
    __________________
    www.swissproductsllc.com
    __________________
     
  12. tark

    tark Member

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    All I know is that both of mine require a lot of force (compared to any other straight pull) to function. I didn't mean to give the impression that I yank on the thing as hard as I can, just that it takes a firm hand.

    As far as I have seen, all of the Swiss straight pulls are rough as a cobb and difficult to manipulate compared to the other straight pulls out there; their high quality notwithstanding. I will never understand how anyone could describe them as "smooth as butter".

    If you want to feel what the queen of all straight pull bolt actions feels like you would have to go into the sporting rifle world and pick up a Ross M-10 sporter in 280 caliber. I have two. It cocks on the initial 3/4 " of travel but the rest of the rearward and forward stroke is as smooth as a Krag. The Ross military rifles were dismal failures, but the M-10 sporter won international acclaim 100 years ago. And the metal finish on both of them is above the Swiss rifles.
     
  13. tark

    tark Member

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    P.S. I have never shot anything but Norma Factory ammo in my Swiss guns
     
  14. Katitmail

    Katitmail Member

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    OP here. Today I shot it again (not the first time). GP11 is ammo I use. This rifle shoots better than me for sure. 50-75 yards will be no problem with deer for sure. I'm shooting open sights. Bolt operates smooth, not much effort needed, ejection always nice, straight over my head. I'm not that experienced with rifles, only one I shot with bolt is Mosin, I like this K31 much better as far as bolt action goes.
     
  15. Jim K

    Jim K Member

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    That gap is fairly common and has nothing to do with the bolt being locked. I have no idea what it has to do with BATFE, unless we are into blaming them for everything.

    Jim
     
  16. Swampman

    Swampman Old Fart

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    @ Katitmail
    You bolt's behavior looks fine to me, all my K31's do that. Just make sure you push the handle all the way forward before you shoot or you're likely to get misfires.

    GP 11 is excellent ammo but don't forget to pick up some good soft point hunting ammo before you go out after deer. The Prvi Partizan 174 grain factory load shot pretty much the same point of impact as GP-11 at 100 yards for my son and performed well on the buck he took.

    @ Jim K
    Nobody is blaming the ATF for anything involving weapon function, just the huge CAI "Billboard" plastered all over the rifle's receiver in the photo with the Op's original post.
     
  17. Swampman

    Swampman Old Fart

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    So it's your belief that the K31 is so delicate that it needs to be handled gently? Odd, but I've never seen anything in the translations of Swiss training manuals to indicate that. I can't imagine that the Swiss counted on their soldiers to "baby" their rifles by gently and slowly pushing and pulling on their bolt handles as they were being attacked by waves of Nazi storm troopers!

    The rifles may be over 50 years old, but if the steel has deteriorated to the point that pulling and pushing sharply on the bolt handle is going to break it, no sane man would even consider trusting it enough to touch off a cartridge generating 45,000 psi just inches from his face.
     
  18. barnbwt

    barnbwt member

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    The Swiss had replacement parts, we do not.
     
  19. tark

    tark Member

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    I must heartily agree with swampman, I doubt a soldier under fire is going to remember not to yank on his bolt handle too hard. And I'm sure the Swiss had lots of replacements, and it probably only took a minute or two for the soldier under fire to whip out his replacement op-rod and..... this is a ridiculous scenario. It seems the Swiss rifles had an inherent flaw, which they never discovered, because they never went to war with them.

    Don't get me wrong, I admire my Swiss 1911 and K-31 for their fine craftsmanship and their superb accuracy.

    They are almost as accurate as My Ross Mk III. (Which I admit, was a dismal failure as a military rifle)
     
  20. tark

    tark Member

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    I thought M-1s and M-14s had op-rods, not Swiss military rifles.
     
  21. Katitmail

    Katitmail Member

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    I bought 2 packs of Hornady soft point, headstamp suggests that its re-labeled Prvi ammo, or just brass?

    Haven't tried it yet to compare where it hits..
     
  22. zfk55

    zfk55 Member

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    Did you two even bother to read my post?? Did I say anything about gentle? So, slamming that bolt in and out of battery is your idea of how it should function, right?
    Ridiculous scenario? Just how much historic inside information on the Swiss armory repair and replacement end of things do you two have? I have a lot, and that's about 50 years worth now.
    Re-read the post, gents.

    Or in case you'd rather not............ think about this. None of those op-rods were made by Eidgenossische Waffenfabrik in Bern. Beginning in the early 1900's and right up until the last ones made in the 50's, those op-rods were made by cottage industries around Bern. They used their own metal formulations and their own hardening processes. Later on Haemmerli was making barrels and a few other parts.

    I've had 285 of them pass through my hands now as we still use them in the manufacture of our Left Hand Op Rod mechanisms. We cut them, we file them we weld them, and I can tell you that the number of them with crystalized steel would surprise you two gents. We have solid working knowledge of the steel and condition of these old original op-rods.
    As new issue those op-rods were quite different than 100 years later............ Or did you not pick up that part in my post?

    Want to slam them in and out of battery? Be my guest. I'm one of the very few in the US that even has them.

    This is a LHO, attached to the op-rod in place of the original bolt handle with our new handle machined.

    lho010_zps06586c0d.jpg


    And Tark,.............. wouldn't it be amazing to find out what a k31 op-rod actually is and how it functions before all those comments?


    The rifles may be over 50 years old, but if the steel has deteriorated to the point that pulling and pushing sharply on the bolt handle is going to break it, no sane man would even consider trusting it enough to touch off a cartridge generating 45,000 psi just inches from his face
    .


    Didn't really think that one through, did you.
     
    Last edited: Nov 3, 2014
  23. tark

    tark Member

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    All I glean from your posts is that the Swiss rifles had a serious, inherent flaw, and its a good thing they were subjected to the rigors of peacetime service and not war.

    Did the Swiss have a uniform standard for both manufacturing the damn things and then testing them for conformity before accepting them into service? Did they have a standard for what kind of steel was used?

    If they did not, and it appears that is the case, then they were stupid.

    And I STILL maintain that they are rough as a cob to operate, especially from prone, and based on what I have learned from you, they would be my last pick among all the straight pulls to take to war. Good thing they are outstandingly accurate, otherwise we could only admire them for their workmanship.
     
  24. tark

    tark Member

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    P.S. It is pretty obvious what a K-31 op rod is and how it functions, what makes you think it is rocket science?
     
  25. zfk55

    zfk55 Member

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    Good grief! I give up. :banghead: :D
     
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