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Thread: Polygonal rifling vs traditonal rifling

  1. #11
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    Quote Originally Posted by vicious_cb View Post

    I'm pretty sure the velocity boost that polygonal bores give cannot be disputed . . . I'm talking about polygonal rifling as found in a noveske and lothar walther barrels

    Au Contraire, Mon Fraire!

    When comparing the muzzle velocities of quality barrels of the same length, it is the type of chamber (including freebore and leade) used in the barrel that will be the greatest determinant of differences in velocities; not the rifling.





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    Quote Originally Posted by vicious_cb View Post

    Also I'm talking about polygonal rifling as found in a noveske and lothar walther barrels which is just rifling without the sharp edges not "true" polygonal bores


    This is correct. The Noveske barrels have definite lands and grooves and are not of the “polygonal bore” type such as found on Heckler & Koch weapons. With the polygonal rifling of the Noveske barrels the sides of the lands are “ramped” as compared to being perpendicular in traditional rifling (as can be seen in the pictures below.)











    Last edited by Molon; 12-07-08 at 00:08. Reason: ...

  2. #12
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    Originally Posted by Broadway:

    John's N4 shoots sub moa all day with match ammo . . .


    Noveske N4 barrels in the AR-15 platform will not shoot “sub MOA all day with match ammo.” They will however average 1.25 MOA, which is damn fine accuracy for a light-weight, chrome lined NATO chambered barrel and more than accurate enough for their intended application.



    Noveske 16" N4 light Recce







    I performed an accuracy evaluation of my Noveske 16” N4 Light Recce upper following my usual protocol. Testing was performed from a distance of 100 yards. Firing was conducted from a concrete bench with the free-float handguard resting in a Sinclair Bench Rest. The rear stock of the rifle rested in a Protektor bunny-ear bag. Wind conditions were monitored using a Wind Probe. A Leupold VARI-X III set at 25X magnification and adjusted to be parallax free at 100 yards was used for sighting.

    Using hand-loaded, match grade ammunition I fired three, 10-shot groups in a row. The extreme spreads of those groups measured:

    1.29”
    1.18”
    1.31”

    for a 10-shot average extreme spread of 1.26”. I over-layed those three groups on each other using RSI Shooting Lab to form a 30-shot composite group. The mean radius for the composite group was 0.37”.

    After firing the above three groups, I fired an additional five, 10-shot groups in a row using the same set-up for a total of eight, 10-shot groups. The average extreme spread for all eight groups was 1.24”. I over-layed all eight groups on each using RSI Shooting Lab to form an 80-shot composite group. The mean radius for that composite group was 0.39”.








    Originally Posted by Broadway:

    I have a "massed produced machine gun barrel" that shoots as well as a match barrel.
    No, you don’t. What you have is a damn fine barrel for its intended purpose. My barrel of choice for my “go to” Homeland Defense Weapon is the Noveske N4 barrel. The barrel is more accurate than I will ever need it to be for its intended application.






    However, I don’t delude myself into believing that the accuracy level of a light-weight, chrome lined, NATO chambered barrel is on par with a stainless steel, single-point cut rifled, match chambered Krieger barrel. As already proven, the N4 barrel in the AR-15 platform will average 1.25 MOA with match grade ammunition. The accuracy level of a Krieger match barrel in an AR-15 platform is far superior to that.


    Testing a 24" Krieger match barrel in the same manner as described above for the N4 barrel, I obtained three 10-shot groups using hand-loaded match grade ammunition at a distance of 100 yards. Those three groups had extreme spreads of:

    0.537”
    0.57”
    0.69”

    for an average extreme spread of 0.599”.

    The three 10-shot groups were overlayed on each using RSI Shooting Lab to obtain a 30-shot composite group that had a mean radius of 0.19”.



    Last edited by Molon; 12-08-08 at 10:09.

  3. #13
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    lothar walthers polygon rifling looks very similar
    Last edited by vicious_cb; 12-24-08 at 21:43.

  4. #14
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    Quote Originally Posted by WS6 View Post
    Lets put it this way. How many polygon rifled bores help win benchrest competitions? How many are entered in that competition?
    While not benchrest, David Tubb wins Camp Perry with Schneider polygonal barrels on his T2K rifles.
    Last edited by Long_Range; 12-08-08 at 23:40. Reason: spelling correction

  5. #15
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    Quote Originally Posted by Long_Range View Post
    While not benchrest, David Tubb wins Camp Perry with Scheider polygonal barrels on his T2K rifles.
    Yeah, Tubb is the man when it comes to long range shootin'. He swears by polygonal rifling. According to him he can get more velocity when using the moly bullets in the polygon rifling. He talks about it on his website and in his book.

  6. #16
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    Again I have yet to see a mfg produce .223 polygonal barrels like what is shown on the right. Which is what tubb uses.
    Last edited by vicious_cb; 12-07-08 at 01:33.

  7. #17
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    Quote Originally Posted by vicious_cb View Post
    Again I have yet to see a mfg produce .223 polygonal barrels like what is shown on the left. Which is what tubb uses.
    Right is polygon, left is standard.

  8. #18
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    Quote Originally Posted by vicious_cb View Post
    lothar walthers polygon rifling looks very similar
    Similar but not the same. The Noveske in Molon's pic looks more like Broughton 5C. If you look at the outline of the bore in your pic (the place where the neck ends), and not the interior (where the rifling spiral shows), you will see a picture like on the below right (the military right ), except your chamber pic is 6 sided (I think, it is hard to tell) and the wiki graphic below is 8 sided:


  9. #19
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    Quote Originally Posted by BretShooter View Post
    Right is polygon, left is standard.
    I think Im becoming dyslexic or something

  10. #20
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    Quote Originally Posted by Molon View Post
    Au Contraire, Mon Fraire!

    When comparing the muzzle velocities of quality barrels of the same length, it is the type of chamber (including freebore and leade) used in the barrel that will be the greatest determinant of differences in velocities; not the rifling.




    Hmm the advantages of polygon rifling are getting less and less! Now I have to ask is there a significant accuracy difference between your krieger 16" and noveske 16"? The krieger uses a match .223 chamber though correct?

    Now all I want for christmas is some data confirming or debunking the "less fouling" and "longer barrel life" advantages of polygon rifling.
    Last edited by vicious_cb; 12-08-08 at 00:54.

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