Mauser Action Feeding Work - CZ 550

Discussion in 'Gunsmithing' started by Nhoro, Dec 23, 2018.

  1. Von Gruff

    Von Gruff GOLD SUPPORTER AH Legend

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    So good to see such a positive result. There is nothing quite like the satisfaction of worrying through a problem and putting the personal effort into the fix. I am sure your efforts will be a great help to others having a similar problem.
    Just another shining example of why this forum is the best there is.
     
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  2. Gert Odendaal

    Gert Odendaal AH Elite

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    I concur, this is a great write-up and explanation. You really did great work , I suggest when completing your PH licence do considering commencing studies to become a gunsmith , you really have the quality and insight into such a trade. I really think you will be great being a gunsmith...few old and knowledgeable gunsmiths has cracked this conundrum as you have done it. Johan Greying is one of the few gunsmiths I know of that knows how to make a Mauser Action/clones there off feed in any circumstances. Making a .500 Jeffery feed in a standard Mauser 98 action is the benchmark of mechanical gunsmith prowess . Thank you for this great write-up, I will definitely study it closely, yes, Von Gruff is another talented mechanical guru who is able to explain a difficult concept in such a way that even a person like me understand the difficult concept as a whole...:A Big Hello::A Big Hello:
     

  3. Nhoro

    Nhoro AH Senior Member

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    T
    Thanks Gert. I am a teacher by training but have been involved in building mining plants for the last 10 years. My mind just can’t leave a mechanical problem alone until I have the solution. Just built that way. I would love to study gunsmithing but there is little chance in Zim.
     
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  4. Nhoro

    Nhoro AH Senior Member

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    I enjoy this forum too. Loads of information and experience and generally people just want to help. Hopefully my post will be helpful to someone out there.
     
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  5. bruce moulds

    bruce moulds AH Fanatic

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    in answer to post 15, yes i think it is crf if the rim is against the boltface and under the extractor.
    what do others think?
    bruce.
     

  6. Bruce

    Bruce AH Elite

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    GREAT article and very well written, the go to guide should my CZ550 458 Win Mag start with feed problens...so far it is behaving excellently.
    Good luck with your Zim PH finals!!!
     

  7. Nhoro

    Nhoro AH Senior Member

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    So, I was doing some practice drills and.... had a jam ! Retried,another jam. The bolt handle was a little hard to lift on that round too, on a dummy round. So I had a good look and noticed the bullet was pushed back into the case. Fixed the problem and all was ok. It started me on another investigation though. It seems that shorter OAL has an impact on feeding as well. So I started some investigating the two rounds that I have right now and comparing the actual dimensions. The attached picture give the dimensions. I noticed a few things-Hornady DGS 480 gr solids will give you an OAL 4,5 mm shorter than maximum. This means that a different crimping groove would give them about 10 % more case capacity and still remain within specifications ! With the .458 win mag reputation, you would think they would give themselves all the case capacity they could. The Peregrine 450 gr is seated well out from the case but also has a couple of mm to spare. Anyway, if you have some missfeeds in the CZ 550, try a longer bullet, The Peregrine round has a longer OAL and feeds easier in my rifle. The Hornady DGS will jam if OAL is reduced by 1-1,5 mm in my rifle. So in the CZ 550 in 458 win mag, the longer monometal solids would appear to offer an advantage in feeding reliability, contrary to everything you read and hear simply because they are longer. Also it seems that factory ammo is often shorter OAL than specified and that doesn't seem logical for the win mag either. They limit case capacity by putting the crimping groove quite far forward on the bullet and leave several mm that could be used for powder. I dont really understand it.

    fgh.jpg bgh.jpg
     
    Last edited by a moderator: Jan 20, 2019

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