|Drill Here, Drill Now|
I do my visual sight-in at the longest shot in my house and then:
Ego is the anesthesia that deadens the pain of stupidity
DISCLAIMER: These are the author's own personal views and do not represent the views of the author's employer.
16" barrel and my hand-loads I zero at 200, which is ~1" high at 100
My 223 and 7.62x39 SBR rifles I zero at 100
If you really want something you'll find a way ...
... if you don't you'll find an excuse.
I'm really not a "kid" anymore ... but I haven't grown up yet either
It's easier to see the differences in a visual graphic. This is the one I use. It also shows why I zero in at 50 yrds.
"If you can't be a good example, then you'll have to be a horrible warning" -Catherine Aird
I don't know if its worth quibbling about this in the context of this post, but that would be some very, very fast 5.56 loads. But the actual difference makes no difference to this conversation. For everyday defensive purposes 50 or 100 are both fine. I prefer to not switch between holdovers and unders myself so I zero at 100.
“So in war, the way is to avoid what is strong, and strike at what is weak.”
The above chart is great. I use the 100 yard zero, as that is what both of my AR scopes reticles want me to use. And it is much easier to figure out, angle of squirrel using it...
kimberkid's results are reasonable in my experience. I have two 16" barrel uppers. With factory Hornady Vmax 55, one produces MV of 2,982 and the other of 2,996 fps. Plugging 2,980 fps MV into JBM ballistics, with 2.5" sight over bore, 6000' Density Alitude, zero at 200 yards -- JBM predicts POI of 1.2" high at 100 yards.
IMO POI of 1" to 1.5" high at 100 yards is a reasonable sight setup for many rifles, especially if the gun owner doesn't want to deal with hold overs/unders for reasonably-sized targets out to 250-ish yards. I've sighted in three hunting rifles for my boss this way.
So ACOG experts ... two more questions. I should know this but I don't.
Is the TA31H made to be zero'd at 100 yards ?
Is the lit up reticle suppose to be "lit up" in dim conditions or does it require direct sunlight / daytime light to light up ?
|fugitive from reality|
Your ACOG has tritum and a fiber optic tube and should glow day and night. Some find the daytime lume to be too bright so they cover the optic tube with electric tape.
You can zero an ACOG at any distance you have a cross hair for, including using the 300 meter cross hair at 25 meters.
'I'm pretty fly for a white guy'.
The tritium really only provides enough illumination to see the reticle in complete darkness. If there is much ambient light but it isn't making it to your fiber optic, the reticle won't light up much. An old trick for guys shooting with ACOGs in the dark when they were lighting up their targets with white lights, was to tape a mini cyalume light stick to the fiber optic and then tape over it completely so it didn't give away their position.
In daylight, ACOG fiber optics do a great job, often too good as they are so bright that they bloom. As SgtGold mentioned, some guys will partially cover the fiber optic element to reduce this bloom.
|Like a party |
in your pants
If I only have a 25yrd range to work with, were should I sight at 25yrds for a 50 or 100 yard zero?
You can run the numbers through an online ballistic program. Make sure all your input parameters are correct. https://www.jbmballistics.com/cgi-bin/jbmtraj-5.1.cgi
Offhand, about 2" low at 25yds would be pretty close to a 50/200 zero. With M4's at 25m, aiming center mass on the zero target (a small silhouette) with bullets impacting the base yields a ~50/200 zero.
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100yd Zero- at the 25, POI is 1 1/2 inch low.
"When its time to shoot, shoot. Dont talk!"
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Correct, assuming a standard 2.5" sight height over bore.
Incorrect, assuming a standard 2.5" sight height over bore. A 50 yard zero produces a POI 1.1" low at 25 yards.
Assuming 2" low POI at 25 yards with the 2.5" sight height, a bullet never zeros. In such a scenario, the bullet's closest arc to the sight line is about 1.7" below line of sight, at around 60 yards. The POI will be about 2" low at 100 yards and about 6" low at 200 yards.
This is how I zero my optics:
Red dots = 50 yds (50-250) no adjustments needed
Compact ACOG = 50 yds (50-250) no adjustments needed
TA11 & TA31 = 100 meters
SWFA Scopes = 100yds
Rimfire Scopes = 50yds
|Veteran of the |
For a 50/200 zero (using a 25 yard range), you want point of impact of 1 1/4 inches low.
This equates to dead-on at 50.
If you get the opportunity at a longer range, confirm your zero. Until then, make sure your group is as tight and close as possible to 1.25 inches low at 25.
"just look at the flowers..."
|Age Quod Agis|
For iron sights I use a 50 yards zero which keeps me center of mass out to 300. For my Burris ar-332, I zero at 100 yards because that is what the hold over compensation dots are calibrated for.
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|Quit staring at my wife's Butt|
I zero at 50 feet because I plink with mine and with my bad eyesight anything farther looks like an aspirin tablet. 200 300 400 yards I wish would need to put a large scope on it which just doesn't look right imo.
I zero'd initially at 50' because front + rear + target just doesn't work that well with my eyes, any more. Now that I've an optic, I'll try it out to 100 yards. If that's successful, maybe I'll even get ambitious and see if there's a 200 or 300 yard range nearby I can try.
"America is at that awkward stage. It's too late to work within the system,,,, but too early to shoot the bastards." -- Claire Wolfe
"Whenever somebody uses 'liberal,' when what they really mean is 'leftist,' they immediately lose my attention." -- Me
I have never heard of someone using a 50 foot zero for anything other than a handgun. Even for a 22lr rifle, 75 feet is a close zero.
Running a couple sample 223 loads through JBM, a 50 foot initial zero produces a second zero of roughly 450 to 500 yards.
"Plinking" at 50 feet with an AR-15 due to vision issues suggests that you (1) need some vision correction and (2) need some level of magnification.
Beware the man who only has one gun. He probably knows how to use it! - John Steinbeck
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