.338 Norma Magnum

Discussion in 'Gunsmithing' started by XringCG, Dec 27, 2011.

  1. XringCG

    XringCG Well-Known Member

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    Just curious why everyone is so paranoid about building the .338 Norma magnum on a 700 long action. They already make after market bolts with the Lapua bolt face for it. The designer of the Norma designed this cartridge for a 700 platform and to fit in a normal size mag box. I really dont see the issue open up a bolt face laterally to .585 the lugs are still lugs your not loosing any metal on the lugs at all due to the nose on the Remington bolt. I keep reading about pressures of the case being brought up a lot but Remington chambers the 700 long action to fire the .300 Ultra mag as it is with an operation pressure of 65,000 PSI and the max pressure of the 338 Norma is around 62,000 PSI so it is under what a standard caliber already chambered and fit for that action. So I don't know why its recommended against building on this type of action. I am planning on starting mine come January and was wondering just what I am missing or are people that afraid to try something.
     
  2. BountyHunter

    BountyHunter Writers Guild

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    I have not heard of any issues with the 338 Norma, particulariy if you change the bolts.


    Have seen more than several built on 700 clones and 2 on the 700. Personally think it is better to just sell the 700 and buy a quality clone, but each to his own.
     

  3. geargrinder

    geargrinder Well-Known Member

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    The issue is that you are increasing the surface area of the bolt face. You've already noted that they run about the same amount of pressure. Same pressure with more surface area puts more load on the lugs and abutments.

    I'm not saying that is is dangerous or safe, just that it is more stress in the action than what the RUM do.
     
  4. XringCG

    XringCG Well-Known Member

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    So is the PTG replacement bolt lugs bigger than factory on their long action replacement bolt with 416 bolt face. Cause if not wouldn't it be just the same as opening up the factory bolt?
     
  5. 300R

    300R Well-Known Member

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    Another consideration may be the bottom lug abutment,the feed ramp needs to be opened up to feed this diameter case which will reduce strength in that area.
     
  6. geargrinder

    geargrinder Well-Known Member

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    A 416 Rigby replacement bolt from PTG has the same dimensions, other than the bolt face, as a Rem 700. Same as opening up a factory bolt. No gain in strength.

    Most of the custom actions that are made for the 338 go to a larger bolt body (0.750") and a slightly larger diameter action to allow for larger lugs on the bolt and larger abutments in the action.
     
  7. Loner

    Loner Well-Known Member

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    depends on more than that. Steels are different, you can about bet that remington is
    not going to any great costs to use the best. Typical steels are in the 40,000 to 80,000
    psi yield strengths, for more money you can easily jump to 300,000 and more.
     
  8. Trickymissfit

    Trickymissfit Well-Known Member

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    most bolts are cut out of pre treat 4000 series chrome moly or 416 stainless steel. On paper the stainless steel looks better till you learn about the characteristics of 416 steel. The C/M is better due to the granular structure alone. A good grade of C/M will have a shear strength of well over 100K psi per square inch of area (some are closer to 135K psi with a good heat treat). The best stainless steel would be MAR-10 (a replacement for 17PH4 rearc melt, but with a better heat treat). The problem with it is cost alone. The blank would run you about $50, and also become a new learning curve to machine. Yet the shear strength will still be in the 135K range (might reach 150K with a certified lot of steel)
    gary
     
  9. shortgrass

    shortgrass Well-Known Member

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    Just because someone in the gun world makes it and sells it doesn't make it a "good idea"! Much isn't "guaranteed" for any particular purpose. Requires "user discression" to either use it or not.
     
  10. sp6x6

    sp6x6 Well-Known Member

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    I am not a gunsmith, but relating my experience.I had a 340 wby and wanted to change to 338 Norma, I had 2 different smiths recommend not to build of of it. In the end Im glad I did because I still have a solid 340, and a Defiance,.750 one pcs. bolt,338 Norma.
     
  11. XringCG

    XringCG Well-Known Member

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    Just got back from the shot show and I got to speak with the engieneer at savage and talked about their 338 lapuas the are plain magnum actions all they did was add 50 thousandths to the lug area of the receiver as a precaution. But its still their regular bolt for every other magnum long caliber with an opened up bolt face. So I would have to say that you wouldn't be shearing off lugs opening up the bolt face to fit the norma and lapua. The bolt body is still .700 and the normal lugs they put in all their rifles.