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Posted: 4/16/2003 8:50:13 PM EDT
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I took my Bushy M4A3 to the range to day for the first time since last fall. The last thing I had done with it was zero it on the 25 meter target, with the EOTech. When I set up at the 100 yard range, the sight wasn't aimed anywhere near where the ullets were hitting. Couldn't even use the BUIS because I had switched from a DPMS to an ARMS#40 and had planned to zero it today, but dodn't get a chance. Anyone had issues with their EOTEch losing zero? |
| was at the range and had also sighted in my eotech at 25 went to 100 and shots were high but in the middle was wondering if you had to aim low like cut the target in half when i did this it was right were i wanted it when i had a trijicon reflex i think the manuel also said something about point of aim at different distances |
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A couple of things: - You really should zero at 50 yards, unless you have a real need for a 25yd zero. - Even the exact same ammo can shoot to a different point of aim in different environmental conditions. - Obviously, a different brand or lot of ammo can't be assumed to shoot to the same point of aim. -Troy |
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Guys, It's just understanding trajectories a bit. I am no expert but here goes. When you are looking through the A2 sights or an EOtech optic, your line of sight is a straight line which is roughly 2.6 inches above the bore of the weapon. When the weapon is fired, the point of impact is going to be 2.6 inches below your point of aim at point blank range. At a certain point the point of aim and the projectile's path will meet. The projectile will then travel over your point of aim for some distance, then there is a secondary crossover point where the projectile will cross your point of aim again. If you are using an M4 barrel and you sight in at 25 meters, the secondary crossover point is about 400 yards. There is a major variance within the 400 yards. At 100 meters, your rounds are probably going to be about 6" high. At 200 meters, your rounds are going to be in the neighborhood of 10" high. As Troy said, a better zero is a 50 meter zero which will have a secondary crossover point of about 200 meters. Using this 50 meter zero method, the variance out to 250 meters is less than 3 inches. Here;'s the link to a great site on trajectories and sighting in methods. http://groups.msn.com/TheMarylandAR15ShootersSite/zerotrajectories.msnw Full-Auto |
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Quoted: A couple of things: - You really should zero at 50 yards, unless you have a real need for a 25yd zero. - Even the exact same ammo can shoot to a different point of aim in different environmental conditions. - Obviously, a different brand or lot of ammo can't be assumed to shoot to the same point of aim. -Troy I was zeroing at 25 meters simply because of the handy 25 meter targets I had. The OKO on my lightweight AR was zeroed the same way on the same day, and was shooting on target at 100 yards. Same ammo, same lot, slightly different weather conditions, not hitting within +/- 2 feet of the zero aiming point |
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I would give it another try. zero it and then adjust the left right up down to see if the adjustments seem to be working right. For example move 8 clicks to the right and 8 down and then back and see if you are on zero again. If problems persist contact EO tech. |
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