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Posted: 12/4/2012 9:43:14 AM EDT
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Strictly been iron sight guy, primarily using RIBZ on carbine 16" AR 15 ,and M1A standard sights. In dealing with no magnification low end red dot sights, different manufactures have different procedure for zero, most 100 yards, 50, some 25, from readiing their instruction manuals. The ballistics don't change with a 50/200 or 25/300 zero (not trying to split microns here-I know this is approximate) but how does this correlate to a red dot sight system? Seems I'm I'm the only one left without understanding this and have spent days trying to get most basic info on this from youtube and other web sites including here.
I'm getting the impression that after a zero per manufacturer spec, where you put the red is where the point of impact will be? Or do you hold with the red dot? If so ...how? Looks like the ACOG is another animal as well with chevrons, so you aim with these if a known range..yes.no maybe? Appreciate any input. |
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A red dot will be just like non adjustable irons. If you have a 300m zero you will hit high between 50m and 250m or so. Your rounds. If you want to precisely hit something you will need to know how low to aim at each distance. However, If you are shooting at a human silhouette you will still get hits even with a center of mass hold at any distance up to about 350m. You will hit low at anything past 300m too and will have to know how high to aim to hit those targets.
Most ACOGs have a BDC reticle which allows you to hold the reticle over the target at the proper distance and not have to use "kentucky elevation". It may not be an exact match for your rifle/ammo but it should be close enough to get hits on target at most distances. Dustin |
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Dustin,
Thanks for quick response and logical explanation. I've got an extensive background in tech, math, science and when you couple this with Obsessive compulsive, and can't easily find the answer to a relatively simple question, I get my gyros spun up and get frustrated. The analogy of fixed iron sights says it all as that's the only way I could see the whole system working. If you read some of the red dot manufacturer's web sites, they leave you with the impression that after you've zeroed, they mystically compensate for all bullet drops regardless of caliber and grain and weapon. Unless you've got a laptop plugged into your ACOG or red dot via USB, I can't really see anything other than what you've explained so succintly. Appreciate it and best regards, Walt |
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if you are a game player, and shoot point blank head shots, remember that the scope is above the bore 1.75" or so, and you will have to hold at the top of the target...
comment on the ACOGS... my Desert Storm Vet TA01 bdc is calibrated for 55 grain... my newer TA31F for 62grain...still close enough... the width of the ACOG stadia lines subtend 19" (width of a man's shoulders) at the indicated distance...what I really like is that 1/2 a stadia line is approximately 10" at the indicated distance... so you can estimate wind drift in 10" increments... at Ft Benning in 2010 it was windy..., I had to hold off about 15" for wind on the 420m MGM flash target (10" plate). |
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I like to zero mine at 50 yards and find it easiest to do so using the targets at the link below. Sorry, work computer will not allow me to make the link hot.
Basically you set up the target at 25 yards and aim for the top dot and adjust until you're hitting the lower dot. There are similar targets available for 75 and 100 yard zeroes. You'll want to verify at your actual zeroed distance, as small variations at 25 yards will be slightly larger at 100 yards. Beyond that, just adjust your hold over based on the distance you're shooting. But remember, your dot is 2 or 4 MOA, meaning 2 or 4 inches at 100 yards/meters (can't remember which), so you'll likely still want it on the target inside 100 yards. Also, your zero at 50 roughly equals your zero at 200. http://www.ar15.com/forums/t_3_18/529846_Sight_in_targets_for_25_50_yards_designed_for_Aimpoint_sights.html |
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Many thanks to all for the tips, targets and info. Pretty much same principles of an iron sight zero at a specified range, then knowing the two points along the arc and applying the hold. I've been using the Winchester Ballistics calculator for the numbers on specific ammo to get bullet drop. As I'd mentioned, the manufacturer's instructions on some of the different brands left me kind of hanging. Guess it's just assumed that everyone knows what's involved in red dot zero and using after that. Appreciate all the help!
Walt |
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