Sighting.

Discussion in 'General Firearms Discussion' started by slade601, May 5, 2014.

  1. slade601

    slade601 Member

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    So I just got a saiga .223 and I plan on getting out tomorrow to try it out. Ive read a lot that says with the 223/5.56 a 50 yard zero will be good at 200 or 250 and just an inch or so high at 100.

    Everything ive read with that is usually with ar standard irons.

    Would this work with the ak in .223? I believe my irons are about 2 inches above the muzzle. And the scope to be about 4 inches above due to the rail.
     
  2. TeaSipper

    TeaSipper Member

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    You have to account for the bullet drop at that distance so you aim higher or recalibrate your scope for it.
     

  3. ajole

    ajole Supporting Member

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    IIRC, the normal AR was 2.6 inches above the bore center, and with the old A1 sights, we zeroed at 25 meters, and that gave you a 250 meter zero as well. The newer A2 sights are done differently, they can do a 50/200 meter zero, though I believe the actual military version is a 25/300?

    In one calculator, it looks like shooting 55 grain 3000 fps bullets with a sight height at 2 inches, you can do a 25/280 zero, but that is 4.5 inches high at 100 yards.

    A 50 yard zereo will only give you 165 yards zeroed, but the bullet is only 1 " high at 100.

    But since you HAVE a 100 yard sight with adjustments, here's what you do, if you don't want to zero at 100 yards. Put your sight on the 100 mark, and zero at 25 yards, but 1 inch low of the center of the target. That will put your bullets zeroed at 100, and now the sight adjustments will work correctly.

    .
     
    Last edited: May 5, 2014
  4. TeaSipper

    TeaSipper Member

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    The bullet actually go up?
     
  5. slade601

    slade601 Member

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    25/100 yard would be fine for me with irons here. I really appreciate this information.
     
  6. ajole

    ajole Supporting Member

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    Ummmm....yes, but no.

    By the way, this is one of those FNG questions, where everyone points and laughs at you.;)

    Here it is. Bullets go where the barrel is pointed, with gravity pulling down the whole way. If the barrel is pointed directly at the target, the bullet will hit low. So, we point the barrel slightly up, and point the scope or sights slightly down, so that the point you aim at, and the point the bullet hits the target at, are the same point.

    Since the barrel is pointed slightly up, the bullets go slightly up. On an AR, they start out about 2.6 inches below the line of sight. The bullet intersects your line of sight at 25 yards, thus giving you a "zero". The bullet continues upward, until gravity manages to pull it back down, thus creating a "ballistic arc", meaning the bullet will be slightly higher than point of aim at the intermediate distances, until it curves back down and intersects your line of sight again, at about 250 yards on the A1 guns. After that, the bullet hits lower the further out you go. So, if you want to hit at 500 yards, you must point the barrel further into the air, so the curve will intersect your line of sight at 500 yards, instead of 250 yards.

    [​IMG]
     
    Last edited: May 5, 2014
  7. SWAGA

    SWAGA No longer broke... Lifetime Supporter

  8. ajole

    ajole Supporting Member

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    "A little known fact is that gravity immediately affects your bullet after it leaves the muzzle."

    Say what?:eek:

    :D

    [​IMG]
     
    Last edited: May 5, 2014
  9. TeaSipper

    TeaSipper Member

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  10. Bull

    Bull Just a Man Supporting Member


    Sorta.......
     
  11. TeaSipper

    TeaSipper Member

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    Just trying to make sense of post #3. You zeroed at 25 meters and it will be zeroed at 250 meters? Won't there be a drop then?
     
  12. SWAGA

    SWAGA No longer broke... Lifetime Supporter

    It crosses the zero line twice, once on it's way up at 25 yards ( hence it hitting high at 100) then on it's way back down again.
     
  13. ajole

    ajole Supporting Member

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    Well....yes.:confused:

    That's why it was high at 100, so it could drop back into POA at 250. If you look at my picture just think of the two points where the arc crosses line of sight as the 25 and 250 meter distances. Past 250, it drops until it hits something...like the ground.
     
  14. TeaSipper

    TeaSipper Member

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    Ok, that makes sense if the 25 yard target is higher than level as I see it in the pic. Is that what you mean?
     
  15. SWAGA

    SWAGA No longer broke... Lifetime Supporter

    No, 25 yards is where the ballistic curve crosses the horizontal line for the first time.
    All the way to the left in the picture.
    Here's a screen shot from my ballistics app:

    ImageUploadedByHi-Point Forum1399343069.996540.jpg

    147 grain 30.06 2950fps FMJ
    Sighted in at 25 yards with the center of the scope 2 inches above the center of the bore.
    The ballistic arc of the bullet crosses the horizon line at 25 yards and is 4.3 inches high at 100 yards and drops through the zero line again at about 325 yards.
    So this would be a 25/325 zero.
    I have to aim 6 inches low at 200 yards!
     
  16. ajole

    ajole Supporting Member

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    Ummm...no.

    The eye, the 25 and the 250 are all on one level. That's why they are on a straight flat line.

    The bullet comes out of the gun at a slight upward angle, 2.6 inches below the line of sight. As it flies forward and upward, 25 meters out it intersects your line of sight exactly where your eye is looking through the gun sights. It goes on going slightly upward as it travels, until gravity overcomes the slight upward trajectory out around 120 yards or so and it starts falling back to earth, again crossing your line of sight at 250 meters, then hitting several inches low at 300 meters, even lower at longer distance.

    On the old A1 sights, there is one adjustment, at longer range you just flip the L aperture, which pushes the butt down when you sight the target, and thus makes your bullet go higher, so that it crosses your line of sight closer than 25 meters, then falls back across the sight line out further than 250 meters.

    The A2 sights let you adjust the sight to specific ranges. The Saiga does as well, if the gun is set for 100 meters and shoots to POA at 100 meters, then you just raise the sight to the 300 meter setting, which makes you push the butt down to sight your target, making the bullet go higher at 100 meters, and crossing back down to POA at 300 meters.
     
    Last edited: May 5, 2014
  17. ajole

    ajole Supporting Member

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    Did you look at that link SWAGA posted? Good info.
     
  18. Visper

    Visper AK = Automatic Killer!?! Supporting Member

    This site is good for comparisons of different types of guns with basic ballistic data and info. I use it for comparing different types of firearms. Maybe looking at it you'll understand the "Arc" better.

    http://guns.findthebest.com/

    The more info the better right?
     
  19. ajole

    ajole Supporting Member

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    I see no ballistics there at all...:confused:

    Aha...gotta click "visualize".
     
  20. Visper

    Visper AK = Automatic Killer!?! Supporting Member

    sorry should have said that... the library is pretty good though, everything from hi-point to Arsenal and .22 to .50 bmg.

    Its a fun site to compare different weapons side by side.