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polygonal rifleing any good

5mmgunguy5mmgunguy Member Posts: 3,853
edited April 2008 in Ask the Experts
Is polygonal rifleing better than regular rifleing? I have been reading claims that the polygonal rifleing lasts longer because it doesn't have all the sharp edges that regular rifleing has for the hot gases and partially burned propellant to work on. And it supposely seals the bullet better. Any truth to the claims?

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    XXCrossXXCross Member Posts: 1,379 ✭✭✭
    edited November -1
    Germans love it for a reason.
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    Mr. GunzMr. Gunz Member Posts: 1,621 ✭✭✭
    edited November -1
    Glock uses it...it works, no cast bullets thought
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    nononsensenononsense Member Posts: 10,928 ✭✭✭✭
    edited November -1
    5mmgunguy,

    It's not a great image but you can see that the smooth radii of this form of polygonal rifling would cause significantly less damage to the jacketed bullets. The smoothness also lends itself to better gas sealing since the bullet jacket doesn't have to be forced down into a sharp right angle at the bottom of the square grooves. There is also less potential for damage to the adherence of the jacket to the core.

    rifling_6rPoly_small1-copy.jpg

    This link is to a better article on the various types of rifling and has the illustration above along with some others for comparison.

    http://www.firearmsid.com/A_bulletIDrifling.htm

    The 'hill & valley' polygonal form is only one variation on a theme and we are seeing a resurgence of multifaceted rifling by major manufacturers here in the U.S.

    Shilen has the 'Ratchet'.
    Broughton has the 'Canted'.
    Obermeyer, Rock Creek and even Remington make the '5R' style.
    Gary Schneider makes a variation as well.
    Lothar Walther makes a traditional German polygonal form in several calibers.

    I have several that I use for comparisons and testing that I like.

    Best.
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    perry shooterperry shooter Member Posts: 17,107 ✭✭✭
    edited November -1
    Hello like many things when it comes to Fire-Arms the BEST depends on intended use. I shoot tons of lead bullets in 1911 type pistols so this Polygonal style would not be the best choice for me . I had a Buffalo Newton that had polygonal rifling regret ever selling and now have a H&K P7. I don't think any records of any kind are held with Polygonal rifling. IT is all a TRADE-OFF. GET BOTH[:p]
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    tsr1965tsr1965 Member Posts: 8,682 ✭✭
    edited November -1
    I am not sure if the barrels in Magnum Research Desert Eagles still use polyagonal rifling, but it was even different than the illustratuin Nononsense uses. I had a MKVII in 44 magnum, and it was a tack driver.
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    crazy charliecrazy charlie Member Posts: 62 ✭✭
    edited November -1
    It was my understanding that the poly configuration had less friction than standard rifling, thus producing less heat and in full auto weapons a higher rate of fire could be achieved.
    My police buddies that used the Glock loved it, but to my knowledge used jacketed bullets.
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    CHEVELLE427CHEVELLE427 Member Posts: 6,750
    edited November -1
    http://everything2.com/index.pl?node=polygonal rifling

    http://en.wikipedia.org/wiki/Rifling



    Lead bullets and polygonal rifling

    The manufacturer Glock advises against using lead bullets (meaning bullets not covered by a copper jacket) in their polygonally rifled barrels, which has led to a widespread belief that polygonal rifling is not compatible with lead bullets. Noted firearms expert and barrel maker, the late Gale McMillan, has also commented that lead bullets and polygonal rifling are not a good mix. However, since neither H&K nor Kahr recommend against lead bullets in their polygonal rifled barrels, it is probable that there is an additional factor involved in Glock's warning. One explanation is that Glock barrels have a fairly sharp transition between the chamber and the rifling, and this area is prone to lead buildup if lead bullets are used. This buildup may result in failures to fully return to battery, allowing the gun to fire with the case not fully supported by the chamber, leading to a potentially dangerous case failure. The other explanation is that Glock's barrels may be more prone than normal to leading, which is the buildup of lead in the bore that happens in nearly all firearms firing high velocity lead bullets. This lead buildup must be cleaned out regularly, or the barrel can become constricted and result in higher than normal pressures.
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    tsr1965tsr1965 Member Posts: 8,682 ✭✭
    edited November -1
    5MM,

    Like Nononsense indicated with the illustration, that is just one form of polyagonal rifling. That is the type most often found in factory glock barrels. I believe that HK also uses something similar on some of their models. Grab a Desert Eagle MK VII, and look thru that tube, and you will see a different form...one that seems to give the illusion of not having any lands. I will tell you that my Glock's, and my DE are extremely accurate.
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