Quantcast
  1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

polygonal barrels

Discussion in 'Handguns: Autoloaders' started by moooose102, May 26, 2008.

Thread Status:
Not open for further replies.
  1. moooose102

    moooose102 Member

    Joined:
    Oct 21, 2007
    Messages:
    3,024
    Location:
    West Michigan
    so what is the deal with the polygonal barrels. i have seen this mentioned several times before. i do not know what they are, and how they make for a better gun. or do they? or is it just another ploy to sell guns.
     
  2. jocko

    jocko Member

    Joined:
    Mar 8, 2008
    Messages:
    1,707
    probably

    more expensive to produce. no more accurate, supposed to be an increase in velocity with a polygonal bbl, how much is another thing. Have to be careful shooting lead out of one though, needs to be throughly cleaned. Glock does not recommend it, kahr also does not recommend lead. Normally a polygonal rifled barrel is a more quality type barrel also.
     
  3. blkbrd666

    blkbrd666 Member

    Joined:
    Apr 1, 2008
    Messages:
    1,301
    Location:
    Georgia
    What modern handguns use polygonal rifling?
     
  4. NG VI

    NG VI Member

    Joined:
    Dec 12, 2007
    Messages:
    4,884
    Location:
    Maine
    Glock OEM barrels are 'hexagonal', same idea, similiar execution, H&K uses them, IMI/Magnum Research Baby Eagles, not sure who else uses them.

    They supposedly give a boost to velocity and accuracy potential because of the increased bullet to bore contact, but I'm not sure how big the gain is.
     
  5. possum

    possum Member

    Joined:
    Oct 12, 2005
    Messages:
    8,942
    Location:
    Concord, N.C.
    glock, h&k, also kahr iirc.

    stay away from using kead loads in these types of barrels, or just insure that you clean them really well and remove all the lead fouling when you clean.
     
  6. atblis

    atblis Member

    Joined:
    Feb 19, 2005
    Messages:
    4,530
    Location:
    Neither here nor there
    Polygonal

    Tanfoglio seems to use them sporadically.
    CZ uses them on occassion (CZ82)

    Not necessarily. The equipment itself is expensive, but if you're producing enough barrels, it is very economical for cranking out mass quantities (like Glock).
     
  7. gaowlpoop

    gaowlpoop Member

    Joined:
    May 26, 2007
    Messages:
    73
    Location:
    Middle Georgia
  8. Jim Watson

    Jim Watson Member

    Joined:
    Dec 24, 2002
    Messages:
    21,970
    As to manufacturing cost, I suspect a hammer forge mandrel with gentle curves will last longer than one with sharp corners. All the stuff about higher velocity and longer barrel life is a case of making a virtue out of necessity.
     
  9. Shadow1198

    Shadow1198 Member

    Joined:
    Jul 10, 2007
    Messages:
    206
    Location:
    Austin, TX
    Here's an example of polygonal rifling:

    [​IMG]

    Technically, it does actually increase the velocity of the bullet as true polygonal rifling does not use lands and grooves and provides a better gas seal. It's not some drastic difference or anything but, it definitely does make one. Not to mention, generally it's easier to clean a true polygonal rifled barrel as there aren't lands and grooves so it is much easier to scrub everything off with a bore brush. The whole issue with not being able to shoot lead bullets through polygonal barrels is entirely due to the increased fouling present with lead bullets. I don't fully understand it but, apparently it's easier for fouling to build up with a polygonal barrel. If there is too much build up it can lead to severely increased muzzle pressure, which could in turn cause a kB.
     
  10. jlh26oo

    jlh26oo Member

    Joined:
    Jun 1, 2005
    Messages:
    1,053

    Glock .45's are octagonal, everything else is hexagonal, and both types are polygonal (I.E. hexagons and octagons are both polygons A.F.A.I.K.)! I like it, especially to make up for some lost velocity in compacts and subcompacts (I.E. kahr)! But it's not as big a factor for me in a full size.
     
  11. DWARREN123

    DWARREN123 Member

    Joined:
    May 1, 2006
    Messages:
    1,749
    Location:
    Between TN & KY
    My GLOCK barrels seem to stay cleaner with jacketed or plated bullets and they are pretty accurate. I don't know if they really do make a lot of difference but they work as good as regular rifling.
     
  12. jocko

    jocko Member

    Joined:
    Mar 8, 2008
    Messages:
    1,707
    downside

    Other than they all say stay away from lead bullets. i see no downside to the polygonal barrel. If its better, I like it. My little 3" kahr pm9 barrel can use all the extra git-up and go with a polygonal bbl, and that is fine with me. the theory sure sounds reasonable.
     
  13. usp9

    usp9 Member

    Joined:
    Dec 17, 2005
    Messages:
    3,645
    Location:
    Bowling Green, Va
    Here's a great shot of a polygonal barrel, (can you name the firearm :scrutiny:)
    Personally I don't think they are "better', just a different way of spinning the bullet. The main advantage, if there is one, may be in the increased velocity and longer life of the barrel. Accuracy may be a wash as well as ease of cleaning, IMO
    [​IMG]
     
  14. schmidtundveßon

    schmidtundveßon Member

    Joined:
    Oct 3, 2007
    Messages:
    73
    Location:
    Croatia
    to usp9:

    H&K P7?
     
  15. atblis

    atblis Member

    Joined:
    Feb 19, 2005
    Messages:
    4,530
    Location:
    Neither here nor there
    Steyr

    Steyr GB
     
  16. Rex B

    Rex B Member

    Joined:
    Apr 5, 2006
    Messages:
    659
    Location:
    Fort Worth TX
    American Arms Escort .380
     
  17. NG VI

    NG VI Member

    Joined:
    Dec 12, 2007
    Messages:
    4,884
    Location:
    Maine
    Why do I have to open my mouth?

    Anyway I wonder if anyone has any chrono data from two barrels of similair length with the same bullets? Maybe like a Glock 26/27/33 and a replacement non-polygynal barrel?
     
  18. Shadow1198

    Shadow1198 Member

    Joined:
    Jul 10, 2007
    Messages:
    206
    Location:
    Austin, TX
    That is most definitely a P7 barrel. :)
     
  19. usp9

    usp9 Member

    Joined:
    Dec 17, 2005
    Messages:
    3,645
    Location:
    Bowling Green, Va
    schmidtundveßon,
    None other. :D
     
  20. moooose102

    moooose102 Member

    Joined:
    Oct 21, 2007
    Messages:
    3,024
    Location:
    West Michigan
    so, if i am seeing correctly, instead of having grooves and lands, it is a barrel with, kind of flat or raised sections that are twisted. for lack of a better explanation. it almost looks a little like a microgroove barrel from marlin. so why do they want you to stay away from lead bullets? not enough engaugement?
     
  21. usp9

    usp9 Member

    Joined:
    Dec 17, 2005
    Messages:
    3,645
    Location:
    Bowling Green, Va
    The bullet to barrel fit is tighter than the more open lands and grooves, therefore the additional fouling from an unjacketed lead bullet increases the pressure over time. In other words, there is no place for the added material to go. Jacketed rounds leave far less material behind in the barrel. At what point it becomes an issue... I don't know.
     
Thread Status:
Not open for further replies.

Share This Page