Polygonal rifling?

Discussion in 'Gunsmithing' started by Inkognito, Feb 24, 2011.

  1. Inkognito

    Inkognito Active Member

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    I'm inching closer to pulling the trigger on the build project on my Sako TRG-S. My gunsmith has been wanting to get me into a polygonal rifling barrel. I don't have any experience with polygonal rifling. My perception is that the it might extend barrel life? I've read differing opinions that it might improve accuracy, but I really do not see how. Is it just a matter of preference or are there some major considerations that I am unaware of? It is a .338 Lapua if that makes any difference. I am looking at a 1/10 twist although Pac-Nor has a 1/8 barrel listed on their sight for .338 Lapua. That seems a bit fast to me.
     
  2. Mikecr

    Mikecr Well-Known Member

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    What choices does that leave you with?
    Who makes a REAL polygonal RIFLE barrel other than H&K and possibly LW?
     

  3. 300R

    300R Well-Known Member

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    I have heard from most reports that there is a slight gain in velocity to be had,go for a 1-9.3 or 9.5 twist if you plan on shooting the 300's.
     
  4. BountyHunter

    BountyHunter Writers Guild

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    Is he talking true polygonal or the canted rifling such as the 5r, 5C.

    Broughton makes a great 5C.

    BH
     
  5. shorty

    shorty Well-Known Member

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    I don't have any hands on experience with it,but I had seen polygonal rifling on two muzzleloaders that were manufactured in the early 1800s. They were both 50cal and I would guess used 200-300gr projectiles, but thats just a guess.

    I would think that although polygonal rifling may not be new it should be effective, especially in the recommended twist rates. Less shearing of gilding metal should make it easier to clean too.

    If you decide to go that route a nice writeup with pics would be appreciated!
     
  6. Inkognito

    Inkognito Active Member

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    I do want to shoot 300s so I will look into a 1-9.5. I don't know who the barrel mfg. is that he gets his from. I'll ask about that. They are true polygonal rifling.
     
  7. dwm

    dwm Well-Known Member

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    Pacnor sell barrels with what they call Polygonal rifling....
     
  8. HighKnob

    HighKnob Well-Known Member

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    I've got a CZ82 with polygonal rifling. It was the first I had seen. Did a bit of reading and if you can believe all you read it should be a bit faster and a lot cleaner. You have to look close in the CZ or you'd think it's a smooth bore. Also someone else said that Glocks are polygonal also. For what little difference it makes here, the CZ shoots as good as any of my pistols of that design.
     
  9. J E Custom

    J E Custom Well-Known Member

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    I do not claim to be an expert on Polygonal rifling and can only give my opinion based on what
    others that have said that have had and used them and anything I have read.

    None of the reports have been favorable compared to other types of rifling In accuracy and the
    consensus seems to be that it does not have the control on twist that other types of rifling does
    (It it not as positive as conventional rifling) and after getting worn it loses all control of the spin
    rate on the bullet.

    It is by no means new and seems to work well with lead bullets and at low velocity With slow
    twist rates (Which may rule it out for LRH).

    With less actual bearing surface it "Could" be a little faster and may offer some advantages for
    full Auto rifles where accuracy is not the prime interest.

    With the current quality of rifled barrels I See no reason to gamble on a rifling system that has
    not proven it's self to the precision guys(Bench rest).

    I like to try new things as much as the next guy, but to invest in a custom rifle and use a rifling
    type that does not offer any gains over conventional rifling and longevity is unknown doesn't
    like a good idea to me.

    But, the more people that try it the more data we will get and maybe my opinion will change.

    So I would recommend that you read as much as you can find on Polygonal rifling and make
    your decision based on the general consensus.

    J E CUSTOM
     
  10. Mikecr

    Mikecr Well-Known Member

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    How do you, or your gunsmith, know they are polygonal?
    Gonal,, Hexagonal, Octagonal,,, etc.. These are 'sides' either flat or rounded at a larger radius than cal.
    you can Google it.

    Let us know who he's talking about, and why he thinks it's actually polygonal.
     
  11. rscott5028

    rscott5028 Well-Known Member

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    I stopped by Shilen the other day to discuss a new barrel for my 6.5x284.

    The feller in the office was encouraging me to order their ratchet rifled barrel. I beleive he told me that they have reports that it bucks the wind just a little bit better.

    I think I'll research this a little more.

    -- richard