What type of rifling for a 260AI?

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by Surgikill, Feb 18, 2013.

  1. Surgikill

    Surgikill Member

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    Mar 4, 2012
    Hey guys, I am planning on building a 260AI platform with a pac nor barrel. It will be 26 inches with a 1:8 twist, my only predicament now is what type of rifling do I get? I can choose 3, 5, or polygonal. I plan on shooting 140 grain bullets which should stabilize fine with a 1:8, however I have the choice of 1:7 with the 5 groove. What would be my best option from these riflings?
     
  2. JayR

    JayR Active Member

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    Oct 20, 2010
    My .260AI has a 6 groove 8.5 twist Hart and it is the best shooting rifle I have, loves everything from 120 TTSX to 140gr Bergers. I think as long as you get a quality barrel, like a Pac-Nor, although I have never used one,you should be fine.I have heard that the 3 and 4 groove barrels are slightly faster, but I have never seen any evidence that proves it. But you will love the .260AI, easiest cartridge I have ever loaded for and the most accurate!
     
  3. CPGfan

    CPGfan Well-Known Member

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    Mar 2, 2010
    In my experience the 3 groove Pacnors are about ~35fps faster than the 5's. I've had a couple of each in 6.5-06AI's and the 3's were always faster w the same powder charge. All were equally accurate, they shot lights out!:):). 8 twist is the way to go for 140's as well.
     
  4. elkaholic

    elkaholic Well-Known Member

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    You definitely do not need a 7 twist. An 8 1/2 twist is sufficient for 140's. As far as # of grooves goes, I've had 3, 4, 5, and 6 and as long as the quality of barrel is good, any will work. The 3 grooves tend to wear a little better because they have wider lands but the .260 A.I. is not a big barrel burner. Some people like the canted lands for velocity and clean up but I can't really see any difference in mine. They are both good and my 4 groove Krieger cleans up as well as my 5r Bartlein......Rich
     
  5. crazyhorse

    crazyhorse Well-Known Member

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    Oct 31, 2004
    I have a 3 groove PAC-Nor in 1/8" in a standard 260. It's a great shooter! It loves the 140 Amax, and shoots the 120 gr TTSX'S sub MOA. The side benefit I have noticed is that it cleans up in 5 or 6 patches of Butch's.