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Thread: .260 Remington and the AR10

  1. #11
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    Quote Originally Posted by 223Rem
    ETA: If you are serious about going with the .260 Remington, it would be prudent to look into handloading and scrap the idea of factory ammo, as most of the ammo is for hunting and not LR precision shooting. The selection of high BC bullets in 6.5mm also warrant the need to handload to achieve optimum performance.
    Big plus 1.

  2. #12
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    Quote Originally Posted by Milkman
    .260 ammo is pretty widely available, it has been around a long time. However, even it it weren't you could simply neck down .308 cases.
    It's actually easier on the brass to neck up 243 brass as it is only a .4 mm increase in diameter.

    Use Winchester if you want good quality at a good price, Lapua if you want the best (for about $15/100 more).

  3. #13
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    Don't forget to pick a fast twist if you want to shoot the high BC bullets (Sierra 142, Berger 140, Lapua 139). 1/8 is ideal, as it will stabilize the big ones as well as the smaller ones (Lapua 123, Sierra 123, Berger 120).

  4. #14
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    I have been shooting .260 Remington for about 6 months in one of my AI-AW's. In the last year, approximately 10 of our local long-range shooters have built or rebarreled rifles in 260 Remington (one or two have gone with the Ackley version of it).

    Why? It's simple-- 260 has better external ballistics than 308, full stop. If you compare the best long-range 308 loads (155 Scenar at 2800-2950fps), the 260 beats it by 20-30% wind drift and 15% drop at 1000 yards, with less recoil. 260 is merely a 308 case necked down to 6.5mm, so it is short-action, and because it shares case dimensions, it fits in every DBM that works with 308.

    The downside of 260--

    No "appropriate" long-range factory ammo is CURRENTLY available. By appropriate, I mean high-BC match bullets in the 130-142gr range. Black Hills is supposed to have some available shortly.

    Good brass is another problem. Remington brass in this caliber has been highly variable. Many shooters get better results necking up Lapua 243 brass, or using Winchester or LC 308 and necking it down. These "forming" options are generally labor intensive to prep the brass the first time.

    Barrel life will be good, but 40-60% of 308's barrel life, so you lose a bit there.



    AR-10 rifles are more finicky for accuracy than bolt rifles, in terms of what loads they "like" and 260 is no exception here. The AR-10 in 260 probably won't be able to get the velocity you can get from a bolt gun.

    hope this helps
    Zak

    ETA- I believe the 2nd place team at the 2006 PRTC used an AR10 in 260.

  5. #15
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    Unless you are striving for BR accuracy, Remington brass is perfectly fine. MOA accuracy at 600 yards from sling supported prone with irons is good enough for me.

    That said, if you want better, the easy way is to neck up Lapua 243 with a Sinclair 6 mm - 6.5 mm expander die.

  6. #16
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    To clarify, the problems we have had here were not accuracy as much as being way too soft.

  7. #17
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    Quote Originally Posted by Zak Smith
    To clarify, the problems we have had here were not accuracy as much as being way too soft.
    Interesting. Being primarily a HP service rifle shooter, the bulk of my reloading is 5.56 LC brass. But I also have a 260 Rem match rifle that I shoot several times a year. The most firings I have on a batch of brass is three (I think) and primer pockets are still plenty tight.

    Maybe you guys are using stiffer loads? I am running a Lapua Scenar 139 over 42.5 grains of H4350.

  8. #18
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    Both myself and another experienced reloader saw this in two different rifles with a lot of different loads. When I was using R-P, with a reasonably mild load, it was leaving smoke rings around 50% of the primers (the primers looked OK.) Primer pockets comparatively loose before first firing, etc.

    My current load is 40.7gr H4350 with a 139gr Scenar, in the Lapua brass. The R-P load was a bit more because it was thinner brass, but still less than 42.5gr.

  9. #19
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    If it matters, I am using Fed 210M primers. I have found that both the 205 and 210 match primers seem to seal tighter.

    Honestly, I have not seen those kinds of pressures/weaknesses in my brass. I will keep an eye on it, though.

  10. #20
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    The reason I say that it's variable and not that it sucks across the board is that a couple other guys have other batches of R-P .260 that seem to be OK.

    I started with 210M's, but got significantly better accuracy with the BR2 in 260 and H4350.

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