AR Sponsor
Posted: 3/19/2006 5:02:26 PM EDT
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i finally got my first ar out to the range, and i got dialed in for 50 yds... i had a challenge from a friend that was with me, he wanted to go 5 shots at 100 yds. i never pass up a challenge so we went for the ghusto, i was on at 50 yds, and landed about 4" high, is this normal? for what its worrth, i waxed his ass with 3 of 5 touching one another. thanks for the ballistics info.... |
How was that again? You zeroed your rifle at 50 .... and were you hitting 4" high at 50? Or 4" high at 100? If it's the latter, then it's normal to have a POA / POI difference if you are dialed at 50and shoot 100. |
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If you're sights are at the proper (2.6") height then your groups should be centered roughly 2" high at 100y (and with a 4moa group that means some will hit 4" high and some will hit spot on at 100y).. If you've got an optic mounted on top of the carry handle then 4" is not unreasonable. |
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i have a variment rig with a 20" bull barrel and a 50mm objective scope on a fla t top upper Also, the guy i was shooting with says he had the same trouble, he was shooting an ar with a 16" barrel at 7.62X39 he claimed to be shoting high at 100 when sighted in for 50 sound right?? thanks |
How high are your rings? A 50mm objective is pretty big. I just ran some numbers even with the scope mounted at 3" over bore, with a MV of 3250 you should only be 2.1" high (assuming standard conditions at 1400' ASL)
I don't have any 7.62x39 data in front of me (I'd need MV, bullet weight and BC). but I'd expect it to shoot within 2-3" high at 100y if it was zeroed at 50y. You guy's aren't zeroing one way (say offhand, or using a sling) they doing your shooting using a bipod or sandbags? If the barrel sin't free floated you can deflect the barrel downward using a sling, and upward using sandbags or bipod near the FSB. |
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Even with high rings there shouldn't be that much parallax from 50 to 100, right? The bore - sight relationship isn't any worse than with iron sights... Depending on the quality of scope, you may have some issues. That should be less than a minute of adjustment, for sure. Were you in the center of the adjustment range or toward one end or the other for your elevation? |
 Where do you people come up with this crap!?I can assure you if the bullet from an AR-15 is POI=POA at 25y (or meters) it most assuredly will NOT be passing through the POA at 250. |
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Parallax is an optical effect where the relationship between crosshairs and target can shift if he moves his eye around behind the scope w/o moving the gun. If he has a good repeatable cheek weld it'll be minimal (and it usually is anyway). He's talking about the trajectory arc, which would depend on the bullet, velocity, and height of the sights. Iron vs. scope wouldn't matter if they're at the same height. As Forest noted, if it's sighted for 50yds it'll shoot high at 100yds. That's normal. |
you will have to excuse my mistake i read it wrong   
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