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155gr Berger vld question

Discussion in 'Ammunition & Reloading' started by Roop, Jan 29, 2016.

  1. Roop

    Roop La Grande Active Member

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    Does anyone have experience with pushing the Berger 155gr vld hunting bullets to 1000yds+ in a .308?

    Before a bunch of people start telling me just to give up and use 175s, let me explain.

    I have but one long range/hunting rifle. it's a T/C Icon Precision Hunter with a Vortex hs-t on it. The rifle is very accurate with lighter bullets, and I prefer to push a lighter bullet faster for hunting, but I keep shots inside of 500yds on game. I want to develop a hunting load using the 155s, and am curious if anyone has tried to push them to 1k. If so, were they stable? I would like to be able to load a couple hundred and practice at longer range with my hunting load. The reason for wanting to push them so far is simply because I have a friend who has a range set up on private land near my work and I would like to hit the far gong.

    What got me thinking about stability was reading Bryan Litz's writing about the 168smk and how it tends to tumble past 800yd. i'm pretty sure that bullet will be supersonic past 800, but what I gathered was as it goes transonic (like 1300fps) it gets unstable, leading to unpredictability at longer ranges. So, if that happens to the 168, is it happening to the 155?

    I tested a few 168gr vld's yesterday and the rifle seemed to like them, so I can try that too, but before I spend $50 on a box of bullets, I want to know if anyone has pushed these past 800yds and found them to be stable. I've had good luck with 168 Bergers in the past, even at mag length in this rifle (2.820"), so I'm hopeful that I can come up with a 155gr load that gives me mid range hunting ability, and long range target ability.
     
  2. Darkker

    Darkker Mesa, Wa Active Member

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    Litz certainly wasn't the one to "out" the 168's, that was at camp Perry LONG time ago. But the thing to understand is why they do what they do.
    The 168's got an impressive Bc from a very steep tail angle, around 13° IIRC. That coupled with a goofy CG/CP.(center of gravity/center of Pressure)
    That combo is what ensured that the bullet would experience catastrophic turbulence and over-turn when crossing the trans-sonic region.
    Work done long ago by Dr. McCoy showed that the best tail angle to compromise between BC and survivability was about 9°. Enter McCoy's work, the camp Perry issue where civilians beat the pants off the military marksmen; the military brought testing toys and told Sierra they WILL build a bullet that was stable== 175 SMK, which was not unlike the original 173gr ball round.

    Litz holds the 9° tail on most of not all his bullets. The 12-15 caliber ogives on a Secant ogive however COULD still give the "bad" CG/CP issue. I've never tried to make the Berger 155's cross. Hornady does.

    Best I can tell you, take a chance and really watch the air on your ballistic calculator.
     
  3. Roop

    Roop La Grande Active Member

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    I just looked over some of my old load data from playing with the sierra 155 palma bullet. looks like i was able to get between 2825-2890 fps on that bullet. If I can do that with bergers, and have acceptable accuracy, then there is a pretty good chance of reliably getting them to 1k. But probably not much more.