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Old 05-04-2010, 03:33 AM   #21
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I know you're going to get the hang of it, 556plinker!

The military uses that 25 meter target to get a 300 meter zero. For the carbine the bullet rises in flight from the muzzle and hits the bullseye at 25 meters then rises more where it's about 4-5 inches high at 100-150 meters then starts dropping and hits the bullseye again at 300 meters. From there on it drops real fast.

Of course you can zero at 100 yards if you want, maybe best from a sandbag rest. Some people like to zero at 50 yards because the bullet stays flat and should be within 2.5" of point of aim from 0-230 meters (which is pretty incredible). This last zero is called the Santose Improved Battlesight Zero.

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Old 05-04-2010, 03:55 AM   #22
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You've all got me fired up and now I'm in information overload mode......I'm going to try everything when I go to the range in two weeks! It all sounds like good advice and hopefully I'll have a GOOD target to show all of you. Thanks, and I really mean it.

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Old 05-04-2010, 12:24 PM   #23
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In actuality, the bullet drops from the moment it leaves the muzzle. AR-15 sights are made to be zeroed at no less than 300 yards (meters really). As such, when engaging targets inside of 300 yards, the bullet "appears" to rise. It doesn't really rise, as it is made of lead and has no aerodynamic lift whatsoever. This is why standard issue sights are marked 8/3. The "3" refers to battle zero (300 meters), which should also be the mechanical bottom of the sight adjustment (the elevation wheel on a standard M-16). The "8" refers to 800 meters, the maxiumum effective range of the weapon with standard ammo (M855).

With standard as-issued sights, it is possible to set the front post so that a sub-100 yard zero can be obtained. I can't imagine why anyone would want to do this, unless they were doing all of their shooting at indoor ranges. After all, it's a highpowered rifle, capable of engaging targets out to 800 meters.

My own rifles (and carbine) are sighted to be two inches high at 100 yards. This gives me enough adjustment left in my rear sight to dial in elevation for 600 yards, which I shoot regularly at a local gun club. I just come up 32 clicks (I have 1/2 minute sights) and presto, on the paper at 600. Bear in mind that at 600 yards, the paper is five feet square with a 36" aiming black! For normal everyday use, I dial it back down to its "zero", which as I've said is two inches high at 100 yards. For engaging bad-guy sized targets, this is adequate precision.

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Old 05-04-2010, 03:45 PM   #24
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I have always been under the impression that a high powered bullet would rise after it left the muzzle.
Hornady says Garandpa is correct. Below is link to Hornady ballistics resource page.
External Ballistics - Hornady Manufacturing, Inc

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Old 05-04-2010, 07:43 PM   #25
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Well of course gravity affects a bullet and if sights weren't designed to compensate for it the projectile would be dropping throughout its arc. If that were true, no way would a bullet fly for 800 meters, it would be in the dirt way before that.

But it does rise because the rifle is angled up slightly when sighting in. If that weren't true then the bullet would hit low on any target at any distance. Standard AR sights are about 2.5" higher than the center of the bore so if you put a properly battlesight zeroed M4 point blank on a target and aimed for the bullseye the bullet hole would be 2.5" low. If you walk back 25 meters and aim for the bullseye you should hit the bulleye (so the bullet rose 2.5"). At 50 meters it's still rising, about 2" high and between 100-200 meters it's 5-6 inches high. Somewhere around 175 meters it peaks out at 7" high and begins its decent. At 300 meters it has dropped back to the bullseye which is why you can zero at 25 meters to get a 300 meter zero.

Beyond 300 meters you have to crank up the elevation knob to 4 (400 meters), 5 and finally 6 to get the 600 meter range with the M4 carry handle. A2 integrated carry handles allow you to try for 800 meters.

ETA: Garandpa has a great sighting method and it's basically the Santose Improved Battlesight Zero. But doesn't sound like you adjust the elevation knob so it will go 4 clicks below 6/3 or two below 8/3.
http://grburnett.us/guns/ImprovedBattlesightZero.pdf

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Old 05-04-2010, 09:26 PM   #26
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My sights only go one click lower than the 6/3 setting. At the 6/3 setting I'm two inches high at 100 yards. With the 80 grain bullets that I use for windy days at 600 yards, I have to adjust my front sight one complet revolution (1.25 MOA) to get enough elevation out of my rear sight. If I use 77 grainers (my normal XTC round) I have just enough elevation in the rear sight to go all the way back to 600.

And you are correct Quentin that the bullet appears to rise because the rifle is ever-so-slightly pointed up (even when zeroed at 25 yards). As you raise the rear sight the rifle points farther and farther up, extending the arc the bullet will fly through. If it was fired truly parallel with the ground it would be in the dirt a long time before 600.

Roy

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Old 05-05-2010, 12:27 AM   #27
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Ah, thanks for clearing that up, Garandpa. (Great screen name, BTW!)

And I tip my hat to you for being able to fire at that distance. 300 yards is as far as I go, just like Uncle Sam taught me before sending me to Vietnam.

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Old 05-09-2010, 04:42 AM   #28
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You should practice proper marksmanship basics and get an accurate zero at 50 yards before making any adjustments. I highly suggest you get a few Marine Corps m-16 manuals and study them. Then practice snapping in using the techniques that are described in the manual. (Here is a link to one. AR15 kits and M-16 Parts From Top quality manufacturers of firearm parts. Learn EVERYTHING in chapter 4). Proper shooting position, cheek to stock weld, sight picture, sight alignment, breathing techniques, and slow steady trigger squeeze. When you have that down, then go to the range and get a proper zero at 50 yards. When you have it, write it down. Then move to the 100 yard range, and get a proper zero for that distance. Dont forget to record the direction and amount of wind when you get that proper zero setting. I am here to tell you that you can hit paper plate size targets at 500 yards all day long with bare sights with an AR 15, if you use proper marksmanship techniques. Or you could just buy a scope like most people, and claim that the rifle wont do it. But I got to tell you that I out shoot them people with scopes on the 100 and 200 yard range all the time. And they are never happy about it.

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Old 05-20-2010, 11:49 PM   #29
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That is what I am striving for and I admire you GREATLY. Like I state before, I am GOING TO LEARN how to shoot the gun to a reasonable degree of proficiency before I put the optics on it. I'm not expecting 1 moa out of this $650 dollar cheapie.....this will be my throw around, coyote, riding around gun that sits behind the seat.....and of course an acceptable SHTF gun.

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Old 05-21-2010, 12:55 AM   #30
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I think that's wise, plinker. So many people these days ignore iron sights when actually they are extremely useful.

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