With the development of smaller high BC projectiles- are larger magnums obsolete for ELR shooting?

Discussion in 'ELR, Ballistics & Bullets Board' started by Eternal Student, Jan 24, 2017.

  1. Eternal Student

    Eternal Student

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    I am NOT talking about hunting just target/steel/varmint shooting. I was just curious what some of you guys thought. I have a friend that built a custom 338 LM a few years ago and he seldom shoots it anymore. He says he get plenty of range out of his 6.5 CM to do what he wants and it's cheaper, kicks less, etc... I am NOT saying a 6.5. CM will out shoot a 338 LM in ELR shooting but he kind of has a point. It's amazing with the bullets Berger(Litz), Nosler, Sierra, etc... are coming out with now. I have taken my 300 WM up against several friends 338 LM out to 2000 yards and have done well. I know I don't have the knock down power they do but it's crazy to see these smaller calibers bullets fly so far and hit targets that only larger rounds were capable of few years ago.
    What say you? Thanks for reading my post and any feed back.
     
  2. 284winner

    284winner Gold $$ Contributor

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    I have to agree that the newest 6.5/7mm bullets out there have certainly given guys with the big 30s and 338s reason to question whether they actually need to be beaten up by all the recoil generated by the magnums. That being said, I don't think you'll see many of them put those guns in the back of their safes to shoot the lighter guns. Many guys just love them 30/338 Cal guns. I don't blame them. There's something about shooting those monster magnums that just can't be replaced by the little guys. Personally I'm exactly the opposite. I love the little guy cartridges as they do shoot as well in big wind and felt recoil is enjoyable. The been there done that mentality has affected me in shooting those thumpers and I'm content with the lighter stuff. My 338 magnum has a muzzle brake but shooting it 100 times a year is fine for me. Seems that recently more slippery small caliber bullets have been unveiled making those guns a real deal contender to even the big 7s. Personally I'm excited about Hornadys 147 eld-m that's made its entrance into the long range circle. Unfortunately I can't find any to purchase as of yet but will pick up a mini truck load when available.
     
  3. Berger.Fan222

    Berger.Fan222

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    The BCs of the smaller bullets may be comparable at the muzzle, but the BC advantage of the best .308 and .338 bullets grows as they fly down range.

    Even with the same BC and muzzle velocity, the heavier (larger caliber) bullets seem to move less in the wind. One day I need to do a careful side by side test of this idea.

    Also, there is no substitute for weight when one needs to deliver energy to a target and not just poke a hole in paper. Even if the lighter bullets are preferred for higher volume shooting, a 200+ grain .308 or a 250+ grain .338 will maintain advantages beyond 1000 yards. Does every shooter need those advantages? Maybe not. But those advantages prevent an honest assessment from declaring them obsolete.

    Finally, how many cartridges have ever been obsolete within a few decades of being used my major militaries in the world? The suggestion is just silly.
     
    Last edited: Jan 24, 2017
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  4. 284winner

    284winner Gold $$ Contributor

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    I have a tendency to believe in some cases, the opposite. As long as the bullet can maintain optimum velocity to hold the Ballistic coefficient, it will rival the lesser or equal BC competitor. You definitely are right about down range BC with heavier bullets but the numbers don't grow so much as they are maintained due to weight as long as velocity is maintained. I think the question regarded targets more so than game so energy isn't a factor. BC is the main objective. A 240 grain bullet with a .6 BC traveling at 2800 fps will still be inferior in wind to a 140 grain bullet with a .6 BC traveling at 3000 fps. Obviously if shooting those same projectiles on large game, it's completely ignorant to think the 140 would be superior to a 240 on a Moose in the Yukon. As you stated, doing a side by side assessment of these scenarios would certainly provide better awareness. I have done similar testing to 800 yards and the smaller, faster projectile with equal BC does outperform the larger projectile traveling at slower velocities even in 30 mph winds. The pendulum is changing in bullets and caliber choice for ultra long range shooting in some cases however some will always have their big 338s across bench bags in the longest ranges with the highest winds. No matter how much the pendulum changes, those guns will always be at or near the top for the longest of ranges.
     
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  5. DocUSMCRetired

    DocUSMCRetired

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    In order to calculate BC, you must use the weight of the bullet. It is in the formula. So a 140gr and 185gr bullet with the same, or similar BC, will retail velocity the same.
     
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  6. 284winner

    284winner Gold $$ Contributor

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    Yes sir.
     
  7. Eternal Student

    Eternal Student

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    BergerFan- I believe BC is highest at the muzzle and then drops as the speed drops. The larger heavier bullets are better when it comes to energy on target just because of the sheer weight. I don't think anyone is doubting that. I think Doc. is saying that if two bullets have different weights/cal. but have the same speed and same BC then in theory they should cut the wind the same and fly the same. That is my understanding also.
     
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  8. Berger.Fan222

    Berger.Fan222

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    I understand that is the theory. In theory, there is no difference between theory and practice ...
     
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  9. mr45man

    mr45man Silver $$ Contributor

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    And then there is the surface area of the different projectiles for the wind to act on.
    Surely that must be a factor ?
     
  10. FatBoy

    FatBoy

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    ^ :)

    I am in the camp that the heavier bullets with the same BC will be inside the lighter bullet at distance. I have seen it way too may times at 1k to believe anything else. A 142 at 2950 against a 105 at like 3050-3100 (rough numbers) the 142 might cut the 10 ring where the 105/107 is just out. Same basic external ballistics, but IMO weight matters in the wind.

    That said, I have seen most (all?) of the die hard magnum shooters drop to stuff like 243win, etc. I believe at the end of the day, even the best magnum shooter can execute more perfect shots with a lighter recoiling rifle over a weekend, giving them an overall advantage. AND, it's 50%-60% cheaper to shoot.

    I'm somewhat torn on this. I find myself going to or staying with medium sized bullets (heavy 6.5s, or heavy 6mm) for match shooting but going to much larger, heavier bullets for hunting. Upon reflection, I think I may be getting old, and don't want to deal with recoil OR track an animal. Is that wisdom or laziness?
     
  11. Berger.Fan222

    Berger.Fan222

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    Yes.
     
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  12. 284winner

    284winner Gold $$ Contributor

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    I think you hit that right on the head as clean as you could. Many of us feel exactly the same way.
     
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  13. Ned Ludd

    Ned Ludd Silver $$ Contributor

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    Assuming they are loaded to equal precision and at equal pressure, the slower, heavier, higher BC bullet will always shoot inside (windage) the lighter, faster, lower BC bullet. Unless the two BCs are reasonably close, you will never be able to push the lighter bullet fast enough to overcome the BC deficit at reasonable (safe) operating pressure.

    This does not mean someone should go out and start loading the heaviest, highest BC bullet they can find. For one thing, the rifle chamber and barrel twist rate may not be optimal for the heaviest bullet available. Modifying/optimizing those parameters will cost time and money, and may not be the best idea if the gains are relatively small. In addition, felt recoil may increase with the heavier, higher BC bullet. This is one reason you don't see many F-TR shooters using the Berger 230 Hybrids. With the right setup, you can push the 230s fast enough in a .308 to have an advantage in wind resistance over lighter offerings. However, if you start losing a bunch of points to vertical because you can't manage the recoil, the reduction in wind deflection doesn't mean very much. Further, some bullet designs simply shoot better out of some setups than others. A high BC bullet that can't be loaded with good precision in a given rifle isn't very useful either. The best bet is to choose the heaviest, highest BC bullet for which you can effectively manage the recoil, that can also be loaded with good precision.
     
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  14. Eternal Student

    Eternal Student

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  15. damoncali

    damoncali Silver $$ Contributor

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    The trouble with comparing (for example) a 150 grain .264 to a 500 grain .510 is that the 500 grain 50 is *very light* for a .50 caliber, and a 150 grain .264 is *very heavy* for 6.5mm. If we're going to compare apples to apples, we're going to need a much bigger bullet, and a much bigger case to make heavy bullets in the big bores shine - bigger than the average shooter will tolerate for a whole lot of reasons. Remember - area goes up as the square of caliber, where weight goes up as the cube of caliber.

    For example, if you scale up a Berger .308 210 VLD to .510 caliber, you'll wind up with a 1000 grain bullet with a G7 BC of about .516 (1.033 G1 BC). I don't want any part of a bullet that heavy being sent at 3000 fps.

    That's the primary reason you see people optimizing at smaller to medium calibers. Another is that it's really hard to find a range to shoot past 2000 yards for most people, and a 6.5 or a .30 will get you there. Going bigger is just expense for no practical reason.

    (I know, ancient thread, but I though it deserves more attention).
     
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  16. LA50SHOOTER

    LA50SHOOTER Gold $$ Contributor

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    Run some ballistics charts & see how much a 15 mph wind effects both bullets & the answer becomes clear (at least for me) why heavier bullets have a very distinct advantage. - Try shooting a 6.5 cal. in a 17-25 mph wind at Raton, NM where I've held off 24-30+ inches at 1000 yds. shooting 800 gr. bullets with a BC of over 1.0. to get to the 10 ring. - Now, lets take it up a notch or so and take it out to 2500 yds. and see how those smaller bullets work out. - even a 5-10 mph wind out at that range makes shooting those smaller bullets something that is mind boggling to try to adjust for.

    My .02

    - Ron -
     
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  17. LA50SHOOTER

    LA50SHOOTER Gold $$ Contributor

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    Come to Montana in August, bring your 6.5 and shoot the E2K match (at 2000 yds.) - Show us how well you can shoot that 6.5
     
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  18. SteveOak

    SteveOak Silver $$ Contributor

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    Montana wind sock.png
    Montana wind sock
     
  19. LA50SHOOTER

    LA50SHOOTER Gold $$ Contributor

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    Wind flags will not be allowed ABOVE the line of fire for this event & there doesn't appear to be to much in the way of tree's & stuff to check either. - A 338 cal. bullet @ 2940 will have a peak trajectory of approx 68 feet @ the 1300 yard point. - I'm betting that 6.5 will need 85 to 90 moa of up from a 100 yd. zero to get to the 2000 yard line.
     
  20. SteveOak

    SteveOak Silver $$ Contributor

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    If they have the same or similar BC, the force of the air would be the same. A 185gr bullet would have more momentum and would retain velocity better. It would slow down at a lesser rate than the 140gr bullet, assuming, as you said, they have the same or very similar BC.
     
    Last edited: Jun 11, 2018

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