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bolt

Discussion in 'Maintenance & Gunsmithing' started by alpinemike, Feb 6, 2010.

  1. alpinemike

    alpinemike Beaverton Member

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    I recently noticed erosion on the bolt face. I clean the piss out of this rifle. However, I am thinking the rifle has been piercing primers, and it has a nice crescent shaped valley right into the face.




    I could use any help and advise. Thanks.............Mike
     
  2. usrifle

    usrifle washington Member

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    That's Gas cutting from around the primer pocket. Judging by your bolt lugs wear marks, i'd be concerned about headspace and lockup.
    It looks like the case head isn't full supported and it's "pushing" the primer on that side of the bolt face.....and gas cutting round the primer pocket.(see the wear from the rim?...It's heavier on that side.)
    Look at the lugs.....it doesn't look like you have full "engagement" on both.
    What ammo are you using? How many rounds through that PSL? Take a good look at your extracter too, see if it's worn. (Gives a clue about lockup).
    usrifle
     
  3. alpinemike

    alpinemike Beaverton Member

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    'What ammo are you using? How many rounds through that PSL? "


    I use Russian 147 grn fmjbt and Bulgarian 147 grn fmj. I have around 600 down range. Rifle was new last March.
     
  4. trainsktg

    trainsktg Portland OR Well-Known Member

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    Does this mean you haven't been cleaning the bolt face?

    In case not (I'm sure you know this, but if not), using that Russian and Bulgy ammo also requires neutralizing the primer residue, usually with a few patches of ammonia (or soap and hot water) followed with regular cleaning with Hoppes #9, oil or whatever you normally use. If the bolt face has been neglected, then I suspect that this may be in part why it is eroding away so quickly.

    Usrifles comments are also sound.

    Keith
     
  5. motoman98

    motoman98 Gresham, OR Active Member

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    Sometimes called "corrosive primers"....basically a salt leftover. We always used warm soapy water to remove; also drawing it into the bbl. with a patch, then solvent/oil.
     
  6. alpinemike

    alpinemike Beaverton Member

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    Thanks guys. Yeah I knew it. I just get soo wraped up in cleaning all the other crap (especially the frigging gas tube!) I must have over looked it one too many times. The other thing I wonder about is the rag I have been wrapping it up in. Could have had trace water or even traces of the burnt primers from cleaning.

    I'll be checking into the head spacing, FP and hoping to purchase a bolt.
     
  7. darkminstrel

    darkminstrel PDX Well-Known Member

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    What are the last two digits of the serial number? 'New' might just be 'new to me' instead.

    Clean corrosive ammo with boiling hot water, not ammonia. You're wanting to wash away the ammoniatic salts, introducing more won't do a thing.
     
  8. usrifle

    usrifle washington Member

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    That's Gas "cutting", it doesn't have anything to do with corrosive ammo.
    Look at the bolt lugs...Look at the wear marks on the bolt face.
    Corrosive ammo would leave "pitting" if not cleaned that would be all over the bolt face.
    Do you have any cases that were fired from this rifle? They would help you understand what's going on there.
    The Bolt isn't fully locking up, the case head isn't fully supported and the primer is "leaking" gases on the unsupported side.
    Run it by a competent 'smith and see what they say about headspace and lockup.
    usrifle
     
  9. goneshooting

    goneshooting Oregon City Member

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    if its a Century rifle or import you should contact and inform them of the problem.
     
  10. Trlsmn

    Trlsmn In Utero (Portland) Well-Known Member

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    +1
     
  11. alpinemike

    alpinemike Beaverton Member

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    It is a century, and by new I mean unfired before i bought it. it's a 1977 build. these are built from surplus parts. The arsenal at Cugir sets aside rifles to export. rifles coming to the U.S. are built on compliant receivers. all numbers match on mine and I put all those ware marks on it. for the most part the rifle operates quite well. At least so it seemed. I'll contact century. I hope it does any good.
     
  12. alpinemike

    alpinemike Beaverton Member

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    Done. You thinks this will do any good?
     
  13. usrifle

    usrifle washington Member

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    Your rifle was built as a military weapon. To legally import it, it was broken down to a kit, then was reassmbled with a US compliant receiver.
    That's why it may have a half ground bayonet lug and a threaded muzzle with a "spot" weld on the flash suppressor.
    Later rifles are built for export.
    usrifle
     
  14. goneshooting

    goneshooting Oregon City Member

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    thats the starting point it may do no good at all or they may fix or replace it .

    getting a new bolt is only temp fix do you plan on replacing the bolt every 600 rds ?

    if they wont fix it maybe they can at least recommend a smith that can .



    here is a link for contact info you could also email them as well

    http://www.centuryarms.com/?page_id=26
     
  15. alpinemike

    alpinemike Beaverton Member

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    Copy that. The rifle has a pinned brake. the receiver is U.S. compliant, (not the arsenal receiver) the scope was married to the rifle at cugir came with the tags to match. I love this rifle. It has proven to be quite reliable so far. The rifle operates fairly smooth, or so it seemed. At this point I'm confidant, one way or another I'll find a way to resolve this.

    PS. Century has recommended the rifle be returned to have the bolt replaced. They will send details concerning shipping, warranties, costs and returns. I will follow up with the details shortly.

    Thanks for the help guys! Much appreciated!
     
  16. trainsktg

    trainsktg Portland OR Well-Known Member

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    Do you mean an ammonium salt?

    Actually there is truth to the quoted statement, but it represents an incomplete picture.

    Water is an excellent solvent for compounds like the salts deposited by corrosive primers in rifle barrels. These salts love water (hense the rust) and as such they are also highly soluable, which is why soapy hot water is the recommended method for removing them. The salts are very quickly washed away. It is also a more thorough method than using an ammonia based cleaner. An ammonia solution is more convienient though, especially at the range, plus it is less messy and is every bit as good as the soapy water treatment if a little extra care is taken. But it must be said, it is the water, not the ammonia that removes the salt. OK...so why use the ammonia? Read on...

    Early on, mercury fulminate primers were used, but potassium chlorate fairly quickly became the 'standard' primer compound, because the mercuric primers had a nasty habit of embrittling the brass. Of course, this was bad for long-term storage, the main reason for using corrosive primers in the first place. Both water and ammonia are excellent at dissolving metallic salts like those containing mercury, but when potassium salts came on the scene, well, the ammonia became ineffective because it can't dissolve KCl. What the ammonia will do is dissolve copper deposits. Every time you fire a round, every little pit and imperfection in the bore gets filled with little layers of salt and copper. If you use just water, you leave some salt covered by copper and there it remains. Over time, the copper will oxidize, become permeable to atmospheric water at which time the salts underneath will grab that water and start the rusting process. So when you use an ammonia solution the ammonia removes the copper deposits and the water removes the salt deposits. Then after all of that you can use your Hoppes #9 or whatever, then your Remoil, then your done.

    Keith
     
  17. usrifle

    usrifle washington Member

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    Very good Keith, couldn't have said it better myself.
    usrifle