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Old 07-20-2009, 07:56 PM
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Whats your Red Dot Zero? 25-50-100 yrds?

I have two sight aiming systems. The ACOG with Doc on top. On that rig I have the crosshairs zero at 100yrds, and the red dot at 25yrds. The Red dot is 8moa, so its pretty much built by design to CQC.

My Aimpoint M4's is zero at 100 yards. When I was practicing drills last weekend, my POI was low at 25 yard shots. I knew this would be the case.

Two questions:
what is your Red Dot Zero, & why?
If you sight in at 100 yards, what is the trajectory supposed to be at 25-50-75 yards. I will shoot it soon enough at the range, but thought you experts could shed lmore light. As always, thanks!
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Old 07-20-2009, 08:08 PM
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i'm no expert....i'll give my opinion anyway tho, cos i have nothing better to do

in the Army they have you zero at 25 meters, because the 25m zero is the same as the 300m zero. at 50, 100, 150, etc you will be holding low to put rounds on target. how much you hold depends on the range in question.


i zero my red dots at 100.

up close, if my life is in danger, i'm going to zip the threat up with multiple rounds and an inch here or there wont make a big of a difference if i'm aiming for upper center mass.
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Last edited by Parabellum9x19mm; 07-20-2009 at 08:11 PM
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Old 07-20-2009, 08:21 PM
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Assuming its a 16inch barrel, with average sight over bore height (for an AR15), and pushing approx 3100fps with a 55grain projectile:

Here are the paths for a 25,50,100 yard zero, choose which one is more applicable to your use and go for it:


Red = 25 Yard Zero_____________________Green = 50 Yard Zero____________________Blue = 100 Yard Zero


Last edited by Derek_Connor; 07-21-2009 at 04:23 PM
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Old 07-20-2009, 08:24 PM
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I sighted mine at 50 m.

figure that any "zombie control" would be between 200 and 0.

At this point, the rifle shoots way better than I do, so 300+ ranges are pushing it.
I'll get better with consistent practice.
HD here would be at fairly close ranges... no 500+ meter LOS around here, and there are better options available at that range.



ETA: Nice graphic, Derek! Good job of illustrating ballistic path. I'll have to look at this again, and evaluate.
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Old 07-20-2009, 08:45 PM
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Awsome graphs!
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Old 07-20-2009, 09:25 PM
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I zeroed my Amipoint initially at 50 yards. Then I moved to 200 yards to check my zero again. I did a little adjusting at 200 yards until happy then shot a few at 50 again for confirmation. The difference between the 50 and 200 at 50 yd was less than I thought it would be.

After shooting it a while I feel comfortable with a 50 yard zero from 0-200 yards and maybe a bit further. The bullet path above and below POA is slightly more than 1" out to around 200 yards with a 50 yard zero, as Derek's graphs illustrate. Personally, if going much further I think I'd opt for a 1-4x scope or something similar.
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Old 07-20-2009, 10:42 PM
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I personally think the 50yard zero is best, thought process here is:

based off Derek's chart's,
with a 25yd zero at 0yards, you have to hold over an inch and a half (not like anyone is gonna be doing much shooting right on top of someone but that's not the point) and at 200yards, your going to be holding under around 3 and a half inches from where you want your impact to hit. with a maximum of almost 4 inches under where you want your round to hit. While one will be able to hit a target at 300yards with no change in aiming height, there's still a margin of 5 inches of change that one will have to figure out distance from barrel to target, adjust height and engage. While some of you are thinking, oh well it's just 5 inches, cant be that big of a deal. 5 inches is the difference of hitting a target between the eyes and missing their head completely. or hitting the center of the heart and hitting the stomach. In a fight your just gonna see that red dot, put that on the target and shoot, and with a 25 yard zero, there's a chance (if your aiming at a vital spot) that you may not get the kill.

With the 50 yard zero, shooting at 0yards, you have to hold over and inch and a half (same as the 25yard zero) and at 200 yards, your still only going to be holding over about an inch and a half. with the max hold under of half an inch at 100yards. well between 0 and 200yards, you have a max span of about 2inches which in my personal [not extremely experienced] opinion, is a much more acceptable grouping than 5inches, where you can still kill while aiming for the heart or eyes.

Think of it like this, your the OPFOR and engaging the enemy (a good guy) pick a point on your body and pretend that's where the dot of the good guy's aimpoint is, now assume the good guy did a 25yard zero and his aimpoint is where the point is. and at various distances, add quarters whether above or below the point is.
i.e. 2 quarters on top of the point for 65 yards, 4 quarters on top for 155. and this will be the point of impact for that distance.

now take that same scenario, and swap out the 25 yard zero with a 50 yard zero and 100 yard zero and do the same thing for various distances. the goal is to have the least amount of quarters from the point of impact as possible to retain the most amount of accuracy and least amount of hold over/under for the various distances.




but that's just a different way of looking at it. whether it makes sense or not is questionable.

That being said I had to zero my aimpoint at 25yards due to range rules (what?)
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Last edited by Garrasa; 07-20-2009 at 10:47 PM
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Old 07-21-2009, 12:25 AM
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50 yard zero. Provides a flatter trajectory with a lesser amount of variance in POA / POI from zero out to about 220 yards. More practical of a range for my needs in LE.

I do zero my 4X ACOG at 100yards, however I tend to deploy that optic under different circumstances. Also keeps the internal BDC accurate. I will zero my Doc Optic at 50 also.
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Old 07-21-2009, 12:30 AM
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i do a 50 yard zero. though i've never really shot anything as far as 200 yards.
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Old 07-21-2009, 12:52 AM
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I personally have mine set at 50yds.

As mentioned before I feel it works best for what my use would be if SHTF. 25/50/100 you should be fine for anything inside the general usage. YMMV
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Old 07-21-2009, 01:04 AM
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I have my TA31F dialed in with a 50 yard zero. So far I've tested the BDC and it works well. I know everything inside the chevron is GTG at 200-250 yards. For a 400 yard shot I do have to place the object between the 4 and 5 hash marks.
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Old 07-21-2009, 01:13 AM
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all my red dots are sighted in at 50 yds, and i can pretty easily (shooting off a bench)make hits on 8" steel gongs by holding in the center at 100 and 200, then at the top of the gong at 300. and i'm not even that good a shot.
i'm not going to shoot a carbine much farther than 300 with a red dot.
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Old 07-21-2009, 01:23 AM
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My Aimpoints, EoTechs and others are sighted in at 50 yards. I can't see real clearly much past that and it seems to be a decent defensive range for me. Besides, a 50 yard zero gives me decent shot making ability to about 200 or 250 yards.
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Old 07-21-2009, 01:52 AM
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My Aimpoint is currently zero'd in at 50m. I'm happy with it at this range
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Old 07-21-2009, 02:11 AM
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Old 07-21-2009, 02:24 AM
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Quote:
Originally Posted by Molon View Post
What kind of data did you use to get such different results than Derek?
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Old 07-21-2009, 04:32 AM
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I prefer the 100yd zero for LE purposes inside of 200yds. The 100yds zero has a flatter trajectory out to 200yds than the 50.
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Old 07-21-2009, 10:39 AM
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Quote:
Originally Posted by nickdrak View Post
I prefer the 100yd zero for LE purposes inside of 200yds. The 100yds zero has a flatter trajectory out to 200yds than the 50.
How do you figure? A 50 yard zero has you within plus or minus 2 inches of your zero out to 200 yards. Most times, well inside that number. A 100 yard zero is at roughly 2.2-2.8 inches below your zero line at 200, depending on which velocity & bullet weight values you want to use.

Did you maybe mean to say "flatter out to 100 yards"? Because I would certainly agree with that.
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Old 07-21-2009, 10:56 AM
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Normally if the RDS is the primary optic and placed in a mount that affords a lower 1/3 co-witness or an absolute co-witness and therefore has a nominal height over bore I would say 50m, set it and forget it.

However this is a "back-up" RDS mounted above an ACOG with an ungodly height over bore. In practice this optic should be used at distances no greater than 20 meters for extremely close shots, after which you should be "dropping into" the main optic for the shot.

I think the OP did right sighting the optic in for 25 meters.
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Old 07-21-2009, 11:13 AM
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I zero'd mine at 50 yards. I think this is the sweet spot for non magnified optics.
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