Zero Range for 16in Recce

#51
Naaman said:
How consistent is this across platforms/loads? Is this more or less a geometric fact, or is it a balance of pros and cons among zero distances?
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The 100y zero is pretty consistent among 14-26" length barrels where the line if sight height above bore is between 1.5-2.75"-ish which i would venture to guess is 90% or greater of rifles with mounted optics.

To use certain features on certain optics you need a 100y/m zero. For example the Schmidt Bender PMII Short Dot 1.1-4x20 requires a 100m zero in order for the bullet drop compensation elevation turret to line up properly.

Its not really "pro's and con's" per se as it's about what the purpose is. On my red dots and iron sights I'll do a 36y zero because im gonna only want keep it simple to aim center of chest between 0-300-ish yards. Same thing for the 50y zero and aiming at chest between 0-200.

This is an excellent explanation of the 36y zero, and different zeroing distances as well:

www.vigilanceelite.com

The 36 Yard Zero

The 36 Yard Zero Target In the recent carbine courses we have discussed various yard lines to zero your rifles along with the pros and cons of each yard line. For those that have attended the courses now know that when it comes to your go-to 5.56 caliber carbine rifle that you would pick...
www.vigilanceelite.com
 
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#52
clcustom1911 said:
The 100y zero is pretty consistent among 14-26" length barrels where the line if sight height above bore is between 1.5-2.75"-ish which i would venture to guess is 90% or greater of rifles with mounted optics.

To use certain features on certain optics you need a 100y/m zero. For example the Schmidt Bender PMII Short Dot 1.1-4x20 requires a 100m zero in order for the bullet drop compensation elevation turret to line up properly.

Its not really "pro's and con's" per se as it's about what the purpose is. On my red dots and iron sights I'll do a 36y zero because im gonna only want keep it simple to aim center of chest between 0-300-ish yards. Same thing for the 50y zero and aiming at chest between 0-200.

This is an excellent explanation of the 36y zero, and different zeroing distances as well:

www.vigilanceelite.com

The 36 Yard Zero

The 36 Yard Zero Target In the recent carbine courses we have discussed various yard lines to zero your rifles along with the pros and cons of each yard line. For those that have attended the courses now know that when it comes to your go-to 5.56 caliber carbine rifle that you would pick...
www.vigilanceelite.com
Click to expand...
The dude in that video, you know he’s operator because he rubber bands a tourniquet to his butt stock.
 
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#53
JimmyJr said:
The dude in that video, you know he’s operator because he rubber bands a tourniquet to his butt stock.
Click to expand...
True. He was Seal for a good while. A lot of different units do that so it's quick access of someone needs one. With tourniquets, seconds count to stop blood loss. In my workplace we all have tourniquets on the same spot on our belts and chest rigs for standardization across all the teams.
 
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#54
Jigstick said:
Going to the range tomorrow to zero a 16in WOA 223 wylde barrel i slapped on my RECCE build. Wondering what distance I should zero this at. Shooting 77g SMKs. Any recommendations? On my MK18s i do 36yd zeros, but that seems stupid for this 16in setup.
Click to expand...

Are you using it like a DMR with an optic? 100 yards and then use an RDS.

Carbine with red dot? Either do the same as your MK18 or do 50.

Anything closer than 50ish yards, aim for the face. 50-200, aim center high (thoracic area), 200+ is suppressive fire anyways and you should be more worried about movement than taking multiple seconds trying to aim at something.
 
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#56
whoosh said:
I can't imagine using other than 100m with a powered scope (intuitve holdovers) and 50/200 with back up sights/dots
Click to expand...

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I think it was mentioned previously, but a blanket 100 y/m zero for all magnified optics isn't always the answer, it depends on the optic, reticle, and ammunition. I've used BDC reticles that needed to be zeroed at 200 yards for the drops to work out, that I could also tune for other ammunition as well. Currently I have the rifle I use for 2-Gun zeroed at 50 yards with the PST II 1-6 with the mil reticle because it works for me. I can get a more precise zero on 6X at 50 with the ammo I'm using and my holds are still pretty simple, basically 0-250 hold dead on, 300 = 1 mil, 400 = 2 mils, and 500 = 3 mils.

Now, my SPR is a different story, that's zeroed at 100, as are my 6.5's and .308.
 
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#59
clcustom1911 said:
Im not sure what branch of service you were in, but the USMC M16A2/A4 zero was put the rear elevation at 8/3z and zero at 33m (36y) in every unit I was with. Shit probably changed since I got out (2008).
Click to expand...
I'm not sure what branch you were in, but the USMC M16A1 was zero'd to 100 meters (not yards) in every unit I was in.
Shit definitely changed since I got out (1983).
We used 55grain ammo, none of this puke tip 62 grain shit.
 
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#62
Occam’s Razor suggests that the Marine Corp full of rifle men have probably worked out the simplest solution at 36 yards. Or the Army at 50 yards.

Pick one and go shoot. The margin of error in either at 250+ Yards under combat conditions is probably more than the statistical errors discussed on the posts before this.

Pick one, shoot the shit out of your rifle with that ammo and that zero out to 350 yards. Switch to the other zero, repeat.

Pick the one with the best results with your ammo in your rifle.

Total rounds at each zero will probably be 50? Cheap money for knowing the actual outcome.

Go forth and conquer.
 
#64
Which is actually the same as the 50 yard zero.

Not saying shoot at 50 and call it good. I am saying either the 36 or 50 will yield a solution as good as most people and rifles could take advantage of / shoot anyway.

Molon said:
Apparently Trijicon disagrees with you. The reticle on my Trijicon Credo HX 1-6 x 24 was specifically designed for a 200 yard zero.



trijicon_credo_hx_reticle_01b-2243971.jpg
Click to expand...
 
#66
AR-15 Zeros and Trajectories


The 100 yard zero with a .223/5.56mm AR-15 carbine is a unique trajectory in that the bullet just “kisses” the line of sight at 100 yards and rides along it for approximately 10 yards before dropping back down below the line of sight. (Technically, the bullet does travel above the line of sight, but by only 0.010”; a fraction of the diameter of the bullet itself.)



100_yard_zero_data_01-1301858.jpg




For all other zeroing schemes, there are going to be two points were the bullet crosses the line of sight; the near-zero and the far-zero. For the near-zero, the bullet will cross the line of sight while traveling upward from the muzzle toward the apogee or “maximum ordinate,” its highest point of travel. For the far-zero, the bullet will cross the line of sight while traveling downward from the maximum ordinate.

Now, when assigning a name to a particular zeroing scheme, it would be helpful if that name gave descriptive information about that particular zero; that is, the name should give us information about the trajectory and how it is unique and differs from other trajectories.

As a point of reference, the Santose Improved Battlesight Zero is often referred to as a 50/200 yard zero, however this is incorrect. It is actually a 50 yard/200 meter zeroing scheme; and this is only with a very few particular combinations of bullet weight, barrel length/muzzle velocity and height of sights above the bore. As an example, a 20” barreled AR-15 A2 firing 62 grain M855 will not match the 50 yard/200 meter IBZ. Neither will a 16" barreled RECCE firing 77 grain MK262, nor a 14.5” barreled M4 carbine firing the 70 grain 5.56mm Optimized "Brown Tip" load. The same concept applies when people refer to a 50/225 yard zero. Only a very few specific combinations of bullet weight, barrel length/muzzle velocity and height of sights above the bore will match that description.

What this is all leading up to is this; except for a very few specific combinations of bullet weight, barrel length/muzzle velocity and height of sights above the bore, a 50 yard zero is a different zero than a 200 yard zero. For a 200 yard zero, we know that this trajectory will produce a far-zero in which the bullet will cross the line of sight at 200 yards in its downward travel from the maximum ordinate. (It is physically impossible to produce a 200 yard near-zero with any of the commonly available loads and barrels lengths used in .223/5.56mm AR-15s.) Other than for a very few specific combinations of bullet weight, barrel length/muzzle velocity and height of sights above the bore, the near-zero of the 200 yard zero will not be at 50 yards.

Conversely, a 50 yard zero tells us that this trajectory will have a near-zero in which the bullet crosses the line of sight at a distance of 50 yards in its upward travel to the maximum ordinate. For those who think that a zeroing scheme must be named after its far-zero, it is physically impossible to produce a far-zero of 50 yards with any of the commonly used loads and barrel lengths in .223/5.56mm AR-15s. The 50 yard zero can only be the near-zero.

Here are a couple of illustrations to aid in understanding some of the concepts described above. Let’s start with the 100 yard zero as a reference point. As described above, with a 100 yard zero, the bullet’s trajectory just “kisses” the line of sight at 100 yards. Now, let’s increase the elevation setting of the sights/scope. As this is done, the near-zero can only move closer and closer to the muzzle. Concomitantly, the far-zero moves farther and farther away from the muzzle.



positive_elevation-1301877.gif





For the next illustration, we’ll start with the 100 yard zero again, only this time let’s decrease the elevation setting of the sights/scope. As this is done, the bullet’s trajectory can only fall away from the line of sight. The bullet will never cross the line of sight again; no zero at all.




negative_elevation-1301880.gif





Other than for a very few specific combinations of bullet weight, barrel length/muzzle velocity and height of sights above the bore, the far-zero of the 50 yard zero will not be at 200 yards; and for all practical purposes it matters not one bit. Whether the bullet crosses the line of sight for the second time (far-zero) at 189 yards, 200 yards, 215 yards or 225 yards will not make the slightest bit of difference in the practical application of the AR-15 as a defensive weapon. In each case we will be holding the same POA (beyond CQB distances) and know that we will be hitting within approximately 2 inches above or below that POA out to 200 yards (or farther depending upon barrel length and load.) You should have an idea what your actual far-zero is when using a 50 yard zero and confirm such at distance when possible, but again it’s most likely not going to be a 200 yard far-zero and again it does not need to be.

Choose your battle-sight zero based on the pertinent facts; not nonsense about “shooting through a cone.” When shooting at human targets, in the grand scheme of things there isn’t going to be any practical difference between a point of impact that has a negative deviation from the point of aim, (e.g. the bullet strikes 1.5” below the point of aim) and a point of impact that has an equal positive deviation from the point of aim (e.g. the bullet strikes 1.5” above the point of aim.) In other words, the absolute value of the point of impact from the point of aim (how far the point of impact deviates from the point of aim, regardless of whether it is a positive or negative deviation) is what we need to be concerned about. Therefore, one of the main points to consider when choosing a battle-sight-zero is this: What zeroing scheme produces the smallest absolute values for the deviations of the points of impact from the point of aim, over the distance that we reasonably expect to engage a human target in our intended usage?

The chart below illustrates the above concept. The chart compares the absolute values of the deviations of the points of impact from the point of aim (0.0 inches on the graph being the point of aim/line of sight) for a 50-yard-zero and a 100-yard-zero, using Hornady 5.56 TAP T2 ammunition.




absolute_value_of_poi_from_poa_02-1301881.jpg





As you can see in the graph above, from the muzzle (0 yards) to approximately 62 yards, the 50-yard-zero has a slight advantage over the 100-yard-zero. Between the distances of 62 yards and 165 yards, the 100-yard-zero has the advantage. From the distance of 165 yards out to the 250 yards shown in the graph, the 50-yard-zero has a distinct advantage over the 100-yard-zero. Choose your battle-sight zero based on the pertinent facts.




molon_signature_005-1357735.jpg


....
 
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#73
whoosh said:
Ah.. yeah. Neither the Navy, Army or USMC sniper courses had psuedo stress courses of fire.. Or predeployment work ups.. and I definitly only shot prone on the square ranges inside the wire during twelve combat deployments.. what a bunch of keyboard dorks.
Click to expand...
Now I wonder if you're like all my friends that are former military.
 
#74
My wholly unqualified opinion is that the only reason to zero a modern rifle (with a magnified optic) at less than 100 yards is if one does not have access to a 100 yard range. And, the major benefit of a 100 yard zero (that has not yet been mentioned) is that 100 yards is about as far as one can shoot and call a light breeze 'negligible' for zeroing purposes. For example, a '5 mph' gun/ammunition combo will experience less than 0.1 mil wind drift in a less than 5 mph wind at 100 yards. Add to that- again with modern rifles- all of your elevation adjustments to account for increased distance to a target, starting with a 100 yard zero, are all in the up direction.

In a rifle employed 'on the clock' and engaging large targets (full sized USPSA/IDPA/etc) an argument can be made for an MPBR zero. But, I would argue it is better to get a 100 yard zero first (to take the wind out of the equation), then refine the elevation at the MPBR distance.
 
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#75
If the farthest you are ever going to routinely shoot is 100 yards, and the only range you have is 100 yards long, then you can build an indisputable 100-yard zero, iron, dot, or magnified.

Anything else is going to be a close estimation, but not confirmed.
 
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#77
hlee said:
In a rifle employed 'on the clock' and engaging large targets (full sized USPSA/IDPA/etc) an argument can be made for an MPBR zero. But, I would argue it is better to get a 100 yard zero first (to take the wind out of the equation), then refine the elevation at the MPBR distance.
Click to expand...

That's how I did my LPVO (Steiner P4Xi)

Set it to shoot high at 100 by the amount that would give a 200 yd zero then refined at 200 and confirmed on steel all the way to 500

Obviously it's a BDC reticle with turrets meant for zeroing and nothing else.
 
#78
Again @Molon with the knowledge bombs of well articulated knowledge.

If your optic has turrets why not zero at 100 then leave it set at .5 mil (200 yard poi) for snap shots. Works for hunting. Then If you have time to dial in perfect drop go for it, if not just send it.
 
#84
Jigstick said:
I just want to be able to point the gun and fuck shit up from 0-500yds with minimal “thinking”
Click to expand...
Unfortunately, if you are looking for a point and shoot solution from 0-500 yards, such a beast doesn't exist- at least on reasonably sized targets.
Molon said:
And yet, it's still one of the finest 1-4X LPVO with a day-light bright red dot that's ever been made.

....
Click to expand...
I don't doubt.
 
#86
n2ishun said:
I'm not sure what branch you were in, but the USMC M16A1 was zero'd to 100 meters (not yards) in every unit I was in.
Shit definitely changed since I got out (1983).
We used 55grain ammo, none of this puke tip 62 grain shit.
Click to expand...
What "special" USMC units were those?

The BZO range did NOT give a 100 meter zero.

Between 77 and 83 I was issued the M16A1 in 2/5, 2/9 and 3/8. Before I transfered out of 3/8 we switched to the A2.
 
#89
sinister said:
ACOG, Steiner P4Xi, and Vortex JM-1 are all set for E-type targets / humanoids 39-40 inches (1 Meter) high from crotch to top of the head. If the outer edges of the range bars are within the shoulders of the E-type, that's your range -- kill it.
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TA31-C-100370_RedCrosshair.jpg

STE5202-3.jpg

p_100030000_7.jpg



If you're trying to shoot clay birds, and salad- or dinner-plate sized targets they're the wrong tool.

You still have to shoot each yard line to see where your barrel and ammo vary from the markings -- just as you would any other sight, iron or glass.

inCollage_20200327_084718630-1024x768.jpg
Click to expand...

This is the way
 
#90
My son has shot 77s out of a 16-inch 1-7 with a TA-01B ACOG to 750 yards, easy. Green Tip, M193, and M855A1 are NOT the projo to use past 400 yards unless you're shooting at something bigger than an E-type.

Obviously you'll get some hits (the Army Championships shoot to 500 yards) but you won't be consistent, and if there's any wind it ain't gonna be pretty.
 
#94
308pirate said:
Before I can give you an intelligent answer I need to know a few things
  1. Does your optic have turrets that are meant just for zeroing, or for both zeroing and dialing elevation?
  2. What kind of reticle is in it?
    1. One with only one reference (duplex, single dot, etc)?
    2. One with BDC stadia?
    3. One with MOA or milliradian stadia?
  3. What do you consider the maximum effective range of your rifle?
  4. What target zone diameter do you consider appropriate for this rifle?
  5. What is the max distance available to shoot over?
Tell me and I can say something intelligent on the subject instead of blurting an answer without knowing fuck all about the equipment and application in question
Click to expand...
This is exactly what was going through my mind when I started reading the responses in this thread. Everybody on here blurting out their pet zero without knowing anything about the OP's setup. So many experts in the world.
 
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#96
JimmyJr said:
The op gave the info he felt like giving and asked for recommendations. The hide delivered.
What’s your two bits of wisdom?
Click to expand...
The fact that the OP gave such limited info only served to indicate that he does not know enough to know what information is relevant or required to receive quality advice. Any attempt to respond with a recommendation, without sufficient relevant and required information, only indicates that the person giving the recommendation also does not know enough about the subject to giving out said advice. Almost this entire thread has been textbook Dunning-Kruger in action.

And you are correct: The Hide delivered. Something. This only serves to prove the proverb that "Something is not always better than nothing."
 
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#97
NC_Libertarian said:
The fact that the OP gave such limited info only served to indicate that he does not know enough to know what information is relevant or required to receive quality advice. Any attempt to respond with a recommendation, without sufficient relevant and required information, only indicates that the person giving the recommendation also does not know enough about the subject to giving out said advice. Almost this entire thread has been textbook Dunning-Kruger in action.

And you are correct: The Hide delivered. Something. This only serves to prove the proverb that "Something is not always better than nothing."
Click to expand...

😅 I'm here for the answer as well. The nice thing about a forum is that is SOMEONE knows, he can set all the others straight at the same time.
 
#98
NC_Libertarian said:
The fact that the OP gave such limited info only served to indicate that he does not know enough to know what information is relevant or required to receive quality advice. Any attempt to respond with a recommendation, without sufficient relevant and required information, only indicates that the person giving the recommendation also does not know enough about the subject to giving out said advice. Almost this entire thread has been textbook Dunning-Kruger in action.

And you are correct: The Hide delivered. Something. This only serves to prove the proverb that "Something is not always better than nothing."
Click to expand...

I certainly understand the ballistics behind a 36yd zero. Zeroing a magnified optic at 36yds doesn't seem nearly as functional as say...zeroing the optic at 100yds...developing DOPE for the used ammo out to the effective range of the specific rifle...using the magnified optic for longer engagements....and then running an offset red dot / micro red dot zeroed at 36yds for closer in targets.
 
#99
Zero range and method has a direct correlation to intended use. For general "don't know how near or far, but I have time to dial" 100 years seems reasonable.

For runnin and gunnin, not so much. My truck gun has a 50/200 yard zero and a 2-12 scope with confirmed dope to 450 yards, because its intended to be useful when I'm away from all the other toys, and I'm uncertain of fire superiority or ranges when on the road. And, it's intended for quick employment with minimal dicking around with the knobs. See bad guy, engage bad guy kinda thing. Also FFP with mil hashes and a dope card on the stock for questimating past 250 or so without dialing.

House gun? Different zero and thought process entirely.

I've been around the M-16/AR15/M4 platform a while, upwards of 40 years of service and lots of shooting on the side for fun. When I think of it, probably close to 100,000 rounds at targets, paper, gongs, animals, etc.

I'm not a sniper, ranger, green beret, navy seal, force recon, infantry, commando. But simpler seems better, at least to me.
 
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