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Posted: 5/16/2007 7:54:41 PM EDT
| I have a eotech sight, had it since I got my rifle a year or so ago. I let a Friend (waukegan Police officer) barrow it for a training day for his SWAT team (his was in the shop getting a trigger job.) I Had the Eotech set for 100yd. he adjusted it to 50' the eotech seems very pissy at shorter ranges he complianed to me all day about how much grief it was giving him. By pissy i mean unless that target is at 50' your going to shoot either high or low. Is this how EOTECH always are or is mine f'ed up? if it is broken is there a easy fix or am i going to have to shell out another $450 for a new sight. |
What shop do you work at up there?? Shore Galleries? Well yea...you will be "zeroed" for one distance. Not to say that you can't hit the target with it at other distances, but you have to realize that if you are shooting at a SHORTER distance than your zero distance, chances are that the gun will shoot LOWER. On the other hand, if you are shooting at distances FARTHER than your zero distance, chances are the gun will shoot higher. This is compounded when you zero the gun at short distances, (<50Yds) The shorter the distance you zero it at, the more off it will be at other distances. The EOTECH is no wizz-bang ultra-whammy sight system. Sounds like he expected way too much out of it. If you dont know how to use it properly, its just dead weight on your weapon. What is the skill level of the shooter?? Just because the guy is a LEO doesnt mean jack. Sounds to me like he needs to put in alot more trigger time and less time complaining about something that is probably his fault. Re-zero it back at 100Yds and leave it alone. Your EOTECH is fine... KyAKGuy |
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| I cant say if it was a shooter error because i havent shot it sense i got it back yesterday. he was just bitching about how hard it was to shoot i havent had a problem with it i was just wondering if what he explain to me was an acctual problem or just his fault. he told me that he was aiming lower and higher for range adjustments. he was just pissed because he see those shows and youtube movie ect. were you see soliders or who ever engaging enemies or targets at variouse ranges without adjustments. i told him they are just good and judging range and know there weapon/sights well enough to be accurate with them. but he is conviced that the optic is broken |
+1. I sure hope that officer knows about height over bore etc... If he's zero'd at 50 and is shooting retention drills at 3 yards, it's gonna be off a bit. |
| like i said i havent shot it since i got it back so i dont know how much it is off by. all i know is that for this particular drill ti was 50' and less. i would have liked if he asked if he could adjust the zero cause i would have said NO!! the reason is the nearest ranger/place i can shoot at 100+yd is a good 45min drive from me. (got to love cook county IL) |
Me..... No im only 17 the officer i lent the rifle to is my cousin. but maybe some day |
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This post just came up in another thread, and I replied as below. I hope that this is going to be tacked in FAQ: First, is it on the carry handle, or on a flattop? If on the flattop, then do this: Simply lay the upper down on the bench, UNLOADED, take out the B/C/CH and look through the barrel at a large target, preferably a 24" X 24" paper or larger. Get the gun stable, and then when you are on the target, just adjust W/E screws to superimpose the Eo's reticle over the center of the target at a distance of 25 yards. If the irons are zeroed, you can simply superimpose the 1MOA center dot over the tip of the front sight. (presuming that you have a mount that allows co-witness; since I use a swan sleeve, mine does not). Fire one shot and see where you are. I will presume that you are using a 55 grain bullet. If you are about 2" low, and fairly close on windage, then move back to 50 yds, and sight in there for precise windage and elevation. With no magnification, 50 yards should be just about right. I usually go dead-on at 50. Then simply start shooting targets at 25, 50 and 100 yards. This will tell you how far off the sight axis that the POI will be at these distances, especially if you are going to be using significantly different bullet weights. Even on a flattop, the Eotech will usually sit about 2-2.5 " above the center line of the bore. This will affect your "maximum point-blank range" (hereafter MPBR): that is, the place where the bullet has traveled up or slightly above the line of sight, and its momentum has decreased sufficiently that gravity is starting to pull it down toward the ground again. Actually, gravity is working on the bullet from the moment it leaves the barrel, but with its initial propulsion energy, and the muzzle canted slightly upward above horizontal, it still is capable of traveling away from the horizontal for some distance. IOW, MPBR is ideally the range throughout which the bullet is going to be less than 3" off the line of sight, without you having to hold over or hold under. Beyond the MPBR, there will be a steady drop of the bullet as it arcs, under influence of gravity, toward the ground. With .223 from a 16" barrel, your velocity will be somewhere around 2600-2650 so the POI will very likely be about 1.5- 2" low at 25, dead on at 50, and then probably about 2" high at 100. This is because you have to "cant" the barrel more acutely upward to reach the higher than normal line of sight, than you would with a low mounted scope on, say, a bolt action rifle. With a flat cartridge like .223, you are first crossing the line of sight at 50 yards, and staying above it to about 200 yards, which is why you'll be high at 100. IOW, forget the trajectory charts you'll see on Hornady boxes (though I love that they do that!), since I believe these usually presume a sighting device 1.5" above the center line of the bore. This satisfies your desire to shoot from 25 to 100 yards without having to worry about hold over or under. Hope this helps...... I don't think there's anything at all wrong with your Eotech. Your cousin doesn't know much about them if he sighted it to zero at 50 FEET. If he zeroed it for 50 yards that is OK, but I doubt that since he had to hold over or under, and that is not usually necessary when shooting between 25 and 100 yards. I doubt SWAT training involved engaging targets beyond that. If engaging man-sized targets, and zeroed at 50 yards, then being 2" low at 50 feet will have no bearing on the hits. That is definitely minute-of-man accuracy. When mounting an Eotech to a carry handle the problem is exacerbated because the sight is another 2" higher above the bore line. |
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No rifle shoots like a laser. Bullets fall as they travel over distance in an arc. This trajectory is something you need to compensate for as distance to your target changes. Depending upon where you zero your optic at, you will have two points on the trajectory where point of aim and point of impact are the same. See this illustration:  50yds is a good battle-sight zero. It keeps the trajectory in close to your point of aim up to 200yds. Also, because of the height over bore of an optic, you are going to shoot low at close engagement distances. (5-30ft.) Edited to add: I just noticed that you said he zeroed at 50 feet! 50 feet is a horrible zero. If you shoot a that rifle at any decent distance, it's going to be shooting incredibly high. Don't zero at such a close distance. Learn to compensate for short engagement distances. |
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There is nothing wrong with your EOTech. This sounds like operator error. The EOTech is not a range finding/compensating optic. It is expected that your point of impact will vary if your distance to target changes and you do not make any adjustments. So even if you had left it at the 100 yard zero and attempted to shoot targets at a different range, you would have found that your point of impact was different from your point of aim. I would hope that your "friend" would have known this.
Check me if I'm wrong, but shouldn't this be reversed? i.e. generally, point of impact is higher at shorter distances and lower at longer, due to the target effectively being moved to a different point in the bullet's arc? Although if it was truly zeroed at 50 FEET (which is a ridiculous zero point, by the way -- 16 yards??!!) this might be different since it's so early in the flight path... Either way, it's not your optic. |
+1, see my post on sighting in and this excellent chart from SalmonAxe. This leaves no need for further discussion for zeroing Eotech at 50 yards. Anything else is, well, ridicuous 
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No offense, but I'd suggest you and your 'SWAT' friend take a course and do some reading on ballistics. And I'd suggest getting lots of range time if this is the first time you've notices this on any firearm. OF COURSE the bullet will be high or low at all other ranges other than the zero range. This is true of ALL sighting systems (EOTech, Aimpoint, Irons, Scopes, Lasers) Firearms are ballistic weapons and as such the bullet travels a curved path - while every sighting system points down a linear path. You friend SHOULD have zeroed at 50 Yards (not Feet), An AR with a 50 yard zero keeps the bullet within 2" of the point of aim from muzzle out to around 240yards or so. With a 50' zero the round will be 2" high around 100' (some 30 yards) and will continue to climb for quite a while (always being high till it get to 400y or so). |
+1....Good point. I could shoot through the EO glass, without the reticle turned on and hit man sized targets accurately at 50" Sheesh! SWAT? Puhhleeeze 
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| Gunfighter..... you're right, I don't understand.... the necessity of zeroing it at such a short range as to handicap yourself at longer ranges. That why the 50yd battle sight zero is useful. It gives you the best trajectory for hitting with a minimal of deviation at varied ranges. FYI.....I do have some personal background in the area you address, and am not just throwing out comments. |
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