20" 260 rem veloctity loss

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by smallbutfierce, May 20, 2013.

  1. smallbutfierce

    smallbutfierce Well-Known Member

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    Anyone have a short 260 that can tell me about what velocity you are getting with 123 amax, 140 amax, or others in that weight range? Trying to run some ballistic comparisons. Might look at make my heavy barreled 308 into a switch barrel with a lw 260 barrel as its mate.

    Thanks,

    Dustin
     
  2. benchracer

    benchracer Well-Known Member

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    I really think you are going the wrong direction here. As a general rule, the larger bores tend to lose less velocity in shorter barrels than smaller bores of the same case capacity. As the bore becomes smaller, slower burning powders are required, which in turn necessitates longer barrels for optimum performance.

    If you want a short barrel, go with the .308. If you want a .260, go with a 24-26" barrel.
     

  3. smallbutfierce

    smallbutfierce Well-Known Member

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    That is what I was thinking, just confirming. It is a barrel that is for sale in the classifieds here and it would cut the weight of my rifle in half. I wasn't sure what the real world loss would be. Couldn't find too much info on it, probably because it isn't a popular idea.

    Thanks
     
  4. jpd676

    jpd676 Well-Known Member

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    "If you want a short barrel, go with the .308. If you want a .260, go with a 24-26" barrel."

    +1

    I have a 243 with a 16" barrel and it gets about 400 fps slower than a 24" barrel shooting the same factory ammo. That sucks.

    I shoot a 260 with a 26" barrel, shooting 140 Amax's it gets 2800fps. I don't know what would happen if I cut the barrel by 6" but I doubt it would be the same rifle.
     
  5. smallbutfierce

    smallbutfierce Well-Known Member

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    That scraps that idea. My short 308 is enough of a dog, no point in shooting lighter bullets slower. Guess I'll just have to go with 300 wsm I always wanted: 26" with a lighter contour, muzzle brake, and flutes. Thanks for the help.
     
  6. BoilerUP

    BoilerUP Well-Known Member

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    20" 260s don't have much trouble hitting 2700fps with 140s or 2900fps with 123s with a moderate load of H4350...at worst, you're looking at 2650fps which still spanks a 308 at intermediate and long range.

    I've got a 260 with a 26" barrel...it will be getting chopped to 20, maybe 21". Don't need the velocity as all my shooting is <650yd, it'll still have plenty of arse for 1000yd should I push it that far, and it'll be MUCH handier for stand hunting.
     
  7. benchracer

    benchracer Well-Known Member

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    2700fps in a 20" barrel? I think you are pretty optomistic. Even 2650fps would be a lot closer to the kind of velocity loss you are going to see out of a .308, which is going to be a lot less sensitive to barrel length than a .260.

    It's possible that I am wrong about this, but I would dearly love to see a chrono comparison of the same loads from a 24" or 26" barrel and a 20" barrel. If you do decide to have your barrel cut down, you could provide some useful before and after data.
     
  8. BoilerUP

    BoilerUP Well-Known Member

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    There are plenty of folks over on Sniper's Hide running 20" 260s reporting 2700fps +/- with 140s. There's one guy with a 18.5" 6.5 Creedmoor that gets 2640fps from Hornady 140gr factory ammo, and two others that have 16.5" 6.5 Creedmoors that get 2550fps with 139s and 2750fps with 123s.

    Here's a 19" 260 that really set my mind:
    My New 19" 260... Shorty

    His 28" 260 ran 2850fps with 142s and 43.0gr H4350, and the same load in his 19" 260 went 2650fps. He bumped up to 43.5gr H4350 and hits 2700fps with the 142 or 140gr Hornady BTHP, and 2725fps with the 140 A-Max.
     
  9. su37

    su37 Well-Known Member

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    Shooting a 140 at 2,700 with a 20" is no problem. Easily done, and you don't need a 24" barrel either.
     
  10. benchracer

    benchracer Well-Known Member

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    The Creedmore factory ammo numbers don't surprise me. A lot of what Hornady has been doing lately has been focused on using special powder blends to get max velocity from 20" barrels. We handloaders don't have access to the same technology that they do. Yet.

    I am, however, VERY surprised by the .260 numbers. The fella in the last example you cited is 1.0 to 1.5 grains under max book loads, according to Hodgdon. What really surprised me is that he is loading to mag length and getting that kind of performance. It sounds to me like he has a chamber cut with a custom reamer, since he is getting a .010" jam with rounds loaded to mag length.

    Interesting stuff!

    As an aside, I have a scout rifle that I built a few years ago in 7x57 with a 19.5" barrel. It is a fun little rifle. Easy to carry and fast handling. I still prefer my long barreled rifles, though. They feel more balanced to me and sit steadier in my hands. That's just personal preference. It seems that I am often squarely in the minority when it comes to things like this.