AR's: sight in at 25 or 50 meter?

Discussion in 'Black Rifle Forum' started by m87, Mar 28, 2010.

  1. m87

    m87

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    What have you adjusted to, and does it make much of a difference?

    I read that 50 meters is the "improved" battlesight zero, so I'm guessing that 25 meters is the "old" one. Either way, it should only be a matter of a few inches high or low out to 300 meters at least.

    The range I went to a few days ago had a 100 meter range, and for some reason, a 30 meter range. So I chose 30 meters and zeroed to that. I guess my current zero is somewhere between old and improved.:embarassed:

    Also, since I didn't have time to adjust my iron sights in addition to my red dot, I was thinking of adjusting my iron sights to line up with my red dot point of aim, at least until I can get to a range again (Have the dot sit right on top of the front sight post). I know it won't be the most accurate this way, but it should work for now. Has anybody else done this?

    One last thing. For those of you with red dot sights, are you really getting 1-2" groups at 100 meters? Are you using complete one piece front and rear rifle rests like those made by Caldwell? I was getting 2+ inch groups at 30 meters. Eyesight is fine. I probably just need more practice and a better gun rest than the provided pieces of wood wrapped in carpet (I don't use a rear rest).
     
  2. DPris

    DPris

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    25 yards/meters is only to get you on paper. It can provide a reasonably close zero at 100 yards. It doesn't guarantee anything.

    I've sighted rifles right on at 25 yards up on the hill behind the house in preparation for an established range session at 100 yards & had them show inches off in elevation & inches off in windage later for formal zeroing.

    If you want to place a bullet precisely at 100 yards (or further), you need to zero at that range & go from there.

    Denis
     

  3. BigDaddyK

    BigDaddyK

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    I zero at 50. That also puts it almost zero at 200 too. I use an eotech and haven't really tried grouping at 100 yet. I'm not too concerned with MOA. I can hit a decent sized group so I'm happy.

    Before I had my Eotech I had my irons sighted in. As soon as I stuck the eo on I adjusted the dot to the top of the sights. Went out and shot and it was a good ways off. I guess the way I shoot with irons is different than with an optic.
     
  4. WayaX

    WayaX Lifetime Member

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    Your zero is wherever you think you'll be shooting. If the rifle is a home defense gun, a 100 yard zero doesn't make much sense unless you live in a mansion without interior walls. Conversely, if you're going to hunt with it, a 25 yard zero doesn't make sense unless you're hunting in a petting zoo.

    Good shooting will group accurately no matter what the zero. The improved battle sight zero is 50 yards. If you do this, you should be no more than 2 inches off vertically up to 200 meters.
     
  5. ken grant

    ken grant

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  6. ken grant

    ken grant

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  7. RWBlue

    RWBlue Mr. CISSP, CISA CLM

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  8. DWARREN123

    DWARREN123 Grumpy Old Guy

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    A long time ago when I was humping one it was 25 meters. 25 meters would put you on at 250 meters. Combat zero.
     
  9. KalashniKEV

    KalashniKEV

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    LOL.

    The military has had it so wrong for so long.

    Do you have any idea how a rifle works?
     
  10. A6Gator

    A6Gator

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  11. WayaX

    WayaX Lifetime Member

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    I stand corrected. I was unaware that a 25 yard zero matched up at 250 yards.
     
  12. MCKNBRD

    MCKNBRD

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    LOL.

    Yep, they have.

    Absolutes suck, eh? :upeyes:

    I carried an M16 for a while, too, and never liked the fact that my zero (as established by some paper pusher somewhere years ago) put my bullets over the shoulder of the average Korean between 150 and 200m. And, to add to it, the super-death-ray 5.56 round starts petering out as a manstopper past about 225-250m, where velocity drops off enough to prevent the tumble/breakup that gave it great performance inside 200m.

    The 50m Santose BSZ keeps the trajectory within a 3" radius above or below sight path to around 250m. That means that in the range where your rifle is MOST effective, you're less than 3" up or down from your line of sight. Thats better for everyone involved, unless you're the one in the sights.

    FWIW, the hunting comment was correct, too. The only thing I have 'zeroed' at 25 yds that I hunt with is my shotgun, because we're doing drives in thick stuff when I use that. And I know how its patterning out to 50yds. My .308 that I deer hunt with is zeroed at 25/200yds, and I have a card on my stock with my dope at 50, 100, 150, 200, 250, and 300yds.

    So, to echo your post's tone, do you have any idea how physics and trajectories work? :upeyes:

    To the OP: go to JBM Ballistics and play around with sight heights and zero distances to see how trajectory is affected by zero distance. Really interesting stuff.

    Byrdman
     
    Last edited: Mar 29, 2010
  13. KalashniKEV

    KalashniKEV

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    The bullets go where ever you put them. If you're shooting over the shoulder of your target at 150-200m then I'd recommend some time on the KD range to understand more about the 5.56 and it's trajectory. Honestly, all it takes is a tiny bit of training and you'll understand the relationship between POA/POI and that regardless of what distance you zero at, your bullet is still going to travel the same path once it leaves the muzzle.


    I just realized you have the appleseed link in your sig... this makes me even more perplexed as to your lack of understanding!

    If you stop rolling your eyes, open your ears, and spend a little trigger time understanding the weapon, I think you'll realize that this really isn't the big issue people make it out to be. It doesn't take an understanding of the "laws of physics" to know where your round is going to impact the target at a given distance. Just practice.

    All that being said, 25m zero for me.
     
  14. RyanNREMTP

    RyanNREMTP Inactive/Banned

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    Mine is zeroed at 25 yards.
     
  15. internal

    internal

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    25 yard zero is too steep of a trajectory.

    At 100-200 yards it's just too high.

    When you look at a 25yard zero vs. a 50yard zero on a graph, the 50yard zero makes way more sense.

    [​IMG]
     
    Last edited: Mar 29, 2010
  16. jem375

    jem375 NRA Life Member

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    I can zero my 308 at 25 yards and it is good out to 225-250 no problem.. Last week I tried that with my AR and it was really high at 100 yards, approximately 6".... So I went and zeroed at the 50 yard mark, much better...
     
  17. m87

    m87

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    Wait.....so If I am reading this chart right, with a 25 yard zero, the bullet drops back to your line of sight at almost 375 yards?? Another post said it should fall back into line at 250 yards?

    That said, this chart does show that a 50 yard zero is back on target at 200 yards.

    So why the discrepancy with a 25 yard zero?
     
  18. cdog533

    cdog533 Zombie Killer

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    Wow, great chart.

    25 yard is too close, 50 too far.

    My opinion is 37m / 300m as stated in one of the links above. Happy medium. That's easy to do at almost any range (37m) and 300m is about the max you'd want for 5.56 anyways.

    How much difference is there if you switch to 62 grainers? Would that shoot flatter?
     
    Last edited: Mar 30, 2010
  19. ChrisTKHarris

    ChrisTKHarris I like to shoot

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    My AR is zeroed at 25 yards, but that chart makes me want to re-zero it.
     
  20. DPris

    DPris

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    Go ahead & zero it at 25 off a solid rest, then run it out to point of aim at 100 off a solid rest with the same load.
    If you're happy with the results, it's your gun.
    Never, on any rifle I own, have I or will I zero using somebody else's theoretical zero distance, and certainly not at 25 yards blindly assuming it'll be good at 200, without actual testfire confirmation. I zero to fit each rifle with a given load (or bullet weight, at least) to a minimum of 100 yards, further if I anticipate shooting further & know the trajectory is high.
    Chuck Taylor told us many years ago at a rifle course he taught that he zeros an AR two inches high at 100 yards & that'll usually carry it out nicely to 250.
    I've never seen any reason to argue with that.

    Far too much emphasis is placed on so-called close-quarters-battle use (especially among those who'll never see battle), and far too many people figure if they're right on at 25 they'll be good way out there. In doing so, the "rifle" part of the rifle is lost in terms of being able to engage a target at rifle distances.
    Denis