| .223 Rem, Federal Fusion MSR 62 gr SP | ||||
| BC = .310 | ||||
| Muzzle velocity = 2750 | ||||
| Scope height = 3 in. | ||||
| Shooting angle = 0 | ||||
| No wind | ||||
| G1 drag function | ||||
| No atmospheric correction | ||||
| Range | 25 y zero | 36 y zero | 50 y zero | 100 y zero |
0 | -2.9793 | -2.9848 | -2.9881 | -2.9909 |
25 | -0.0189 | -0.8531 | -1.3463 | -1.7719 |
50 | 2.6381 | 0.9751 | -0.0079 | -0.8563 |
75 | 4.9746 | 2.4828 | 1.0099 | -0.2612 |
100 | 6.9724 | 3.6518 | 1.6891 | -0.0048 |
125 | 8.612 | 4.4627 | 2.0101 | -0.1066 |
150 | 9.8727 | 4.8946 | 1.9521 | -0.5873 |
175 | 10.7319 | 4.9251 | 1.4927 | -1.4695 |
200 | 11.1658 | 4.5302 | 0.6079 | -2.777 |
225 | 11.1484 | 3.6841 | -0.728 | -4.5357 |
250 | 10.6521 | 2.3591 | -2.5429 | -6.7733 |
275 | 9.6471 | 0.5253 | -4.8665 | -9.5197 |
300 | 8.1011 | -1.8494 | -7.7311 | -12.807 |
| MIN | -2.9793 | -2.9848 | -7.7311 | -12.807 |
| MAX | 11.1658 | 4.9251 | 2.0101 | -0.0048 |
| RANGE | 14.1451 | 7.9099 | 9.7412 | 12.8022 |
| AVG | 7.039846 | 2.061808 | -0.88069 | -3.42009 |
| MEDIAN | 8.612 | 2.4828 | -0.0079 | -1.7719 |
| SD | 4.590375 | 2.681887 | 2.964079 | 4.001528 |
-
Having trouble using the site?
Contact support
36 yard zero
- Thread starter deersniper
- Start date
D
Deleted member 10043
Guest
That is correct and we want a vital zone size. Let's say 12". For a typical 7.62x39 that would be about a 330 yard zero with a 400 yard MPBR. So, the accuracy of the shooter/rifle combo should dictate the appropriate zero. What would be the appropriate vital zone size for a 36 yard zero? What would be MPBR?
^^This. The 36y zero strikes me as irons-centric due to desire to hold-under. It drives the impacts 4-5” high (acceptable error for BASIC marksman) for the greatest period.
Dissenting opinion.... Hold-unders are not intuitive, and not necessary.
100y zero...
MUCH tighter group all the way to 150y...,at which point you should know (and be using) your DOPE. As Franks says, distance buys you time and opportunity. You should not need to take rushed shot at >200y, so rushed you have no idea the range.
To use a 36y zero is to say this 250-300y rushed UKD shot is more important than having less error at <200y... and also so important you create hold-unders for that entire range.
By the way, the 36y zero goes to shit quick around 300y. Why is 300y significant?
Bottom line, we should be using DOPE at any distance beyond which your drop from POA is no longer acceptable... not advocating aiming 5” low at closer ranges.
Just my 2 cents. #notaformerseal
D
Deleted member 10043
Guest
Fundamental
www.thetruthaboutguns.com
Do You Know Your Rifle's Maximum Point-Blank Range? Guns for Beginners - The Truth About Guns
John Farnam writes [via ammmoland.com]: Conversations with “precision riflemen” often get into tedious, esoteric mathematical realms, and usually very quickly. Many factors influence the bullet during the brief fraction of a second (sometimes longer) while it is in free-flight between when it...
www.thetruthaboutguns.com
And speaking of MPBR.... It’s great for beginners, arfcom bubbas specing their rifle for battle, and hunters without LRF.
As a forum for true marksmanship, we can do better than “that’s close enough for zombies and looters”. Seriously, have a better reason for what your zero is.
Also, notice the article’s author defines MPBR as 6 centimeters. That doesn’t get you to 300y with 36y zero. It gets you ~50y farther than a 100y zero does... with all the negatives I already mentioned.
As a forum for true marksmanship, we can do better than “that’s close enough for zombies and looters”. Seriously, have a better reason for what your zero is.
Also, notice the article’s author defines MPBR as 6 centimeters. That doesn’t get you to 300y with 36y zero. It gets you ~50y farther than a 100y zero does... with all the negatives I already mentioned.
Uh, LOL. OK there.
Some of y'all clearly didn't grow up with rifles, shooting iron sighted BB guns and then 22 LR out past the "accepted" limits of the cartridge. Hold over with irons is absolutely an effective way to shoot, and has been for hundreds of years before optics became mainstream.
Yes to all of this 100%. The whole 36/300 yd thing (which only really fits a 20" 5.56 anyway, not AKs, 300 Blk, or SBR 223 rifles, etc) seems to be a great method for "lowest common denominator" infantry training for shooting at full size torsos, but as educated marksmen we can do a lot better. Personally I'm not in the infantry and my applications are significantly different; if I need to kill something with my rifle, I may be shooting at much smaller targets than a torso. For me at least, having shot rifles since I was a kid, hold overs at longer distance is intuitive but hold under at 100 yards is definitely not.
You make a lot of good points that echo my own experience and sentiments. I don't claim to be any sort of military expert, ex seal team 6, etc, but for me and my rifles I want POI closer to POA than what a 36/300 yd zero gives.
Also - it does seem most guys miss the point of how to properly set up a 36/300 yd zero: don't just zero at 36 yds and think you're good. 36 is just to get you close, you have to actually shoot at 300 and adjust your zero for that. Just zeroing at 36 is lazy and ineffective.
dude is also talking about setting dope on carbines, not on precision rifles.
chances of you taking 300yd shots with a carbine is slim.
in a 2 way range, getting rounds on target fast is more important than getting that perfect shot.
D
Deleted member 10043
Guest
The problem is it could be anywhere between 25 and 50 setting up a zero that close to the shooter. You just think you have a 36 yard zero. So, as a forum of marksmen what is the other zero for this so-called 36 yard zero? I think it is ridiculous that when the 36 yard zero begins to fail under debate we start referring to it as a Master's Degree zero, lol. Most you guys use optics. You're limited to click values. 36 yard zero.
Ok. Feel free to hold your front sight post over the silhouette of a man shooting at you. Then you can be one of those people that says "fIvE FiVe SiX dOeSn'T KiLl" when you pull the trigger and the dude doesn't die. Except it'll actually be because you missed.
The only holdover that makes sense is zeroing with a 6 o clock hold at distance X and knowing how it doubles as a waterline hold at distance Y
I’d say use whatever combat zero you want and enables you to get rounds on target fast. 25,36,50,100 whatever works. In many cases, your zero distance will be dictated by the optic/reticle you choose.
I now use a 50 yard zero for my 10.3 with an Eotech EXPS 3-2 as it has two dots for hold overs. The center dot is for 50/200, bottom dot is for a 400 yard hold over.
My 14.5 block II wears an aimpoint T1 and I run a 36 yard zero on it and it’s POA=POI at 300 using IMI XM193, M855 and BH 77g OTM. Test it relatively often as I do with the 10.3’s hold overs.
The best combat zero for you is the zero that helps you solve whatever problems you need to solve quickly and effectively with your carbine.
Trigger time and familiarity with your weapon is much more important
I now use a 50 yard zero for my 10.3 with an Eotech EXPS 3-2 as it has two dots for hold overs. The center dot is for 50/200, bottom dot is for a 400 yard hold over.
My 14.5 block II wears an aimpoint T1 and I run a 36 yard zero on it and it’s POA=POI at 300 using IMI XM193, M855 and BH 77g OTM. Test it relatively often as I do with the 10.3’s hold overs.
The best combat zero for you is the zero that helps you solve whatever problems you need to solve quickly and effectively with your carbine.
Trigger time and familiarity with your weapon is much more important
He almost lost me opening up with EOtechs are the best but I powered through.
Good food for thought though. He could have made a much more convincing argument if he would have added that we’re expecting 2MOA out of these guns so theoretically that 25M zero is whatever it was 12” high but potentially half those rounds are more than 12” high and possibly as much as 18” high at 300 but his 36m zero is still within 12” for all of them.
I will say you need to do the math for your gun, ammo, expected distance and acceptable deviation between POA/POI.
Good food for thought though. He could have made a much more convincing argument if he would have added that we’re expecting 2MOA out of these guns so theoretically that 25M zero is whatever it was 12” high but potentially half those rounds are more than 12” high and possibly as much as 18” high at 300 but his 36m zero is still within 12” for all of them.
I will say you need to do the math for your gun, ammo, expected distance and acceptable deviation between POA/POI.
Another great point. Many folks are moving to higher mounts to work better with Nv. That’s gonna change some of the geometry of the zero range.
And barrels are getting shorter. 36 yards is a better zero for an M16 with M855A1 than for an SBR with AA53. And it depends on your standards. Whether it’s torso shots or consistent CNS/heart shots.
D
Deleted member 10043
Guest
I want my target to be within my FOV. If I obscure the target with my front sight post, it will no longer be within my FOV.
D
Deleted member 10043
Guest
You can't always get what you want but sometimes you get what you need.
Its clear you didn't learn much by being lucky as a kid.
When you no longer have any target available to cut with the post, it becomes all luck.
If you hide the target with the post, you are purely guessing.
Ask an IHMSA shooter, if you can "hold over" with iron sights with precision.
What do you mean by “adjust your zero” for 300 relative to 36 yards?
My 14.5“ Block II / Aimpoint T1 is zeroed for 36 yards and hits dead on POI when aiming at an 8” disc at 300. I never have to adjust the zero, just simply point and shoot.
On standard ipsc steel, assuming a desired impact at top 1/3rd center mass , I hold at the belt buckle area if target is at 200 yards and belly button area if at 100. This is with 55g, 62g, 75g and 77g factory and hand loads.
Perhaps you are referring to hold-off to compensate for reduced muzzle velocities out of SBRs?
When my 10.3 was zeroed at 36 I would have to hold top of target to hit high center mass using XM193. Not much of a “ding” with that little bullet at those speeds but it was consistent.
Tsk,tsk,tsk,tsk.......its all about hitting the "credit card" man. You need to work on your operatin'
When I zero I get lazy too and send a group at 50 or 25 or whatever and call it quits. But I get his point. The point of a 300 or 200 or whatever meter zero is to be zeroed at that distance, so you should make sure that you're there instead of just hoping or math'ing or ballistic calculatoring.
The point is to actually zero at the far distance (300) not at the near distance (36 yd). If you zeroed at 36 and are actually dead on at 300, you got lucky. Especially considering the trajectory of different loads, and that you're using a shorter barrel. Most likely a true 300 yard zero in your rifle has a near zero closer to 30 yards, but the difference is small fractions of an inch at the near zero, compared to inches at the far zero.
Why would anyone care about being zero’d at 300y.... or 250y? I’m not following the significance.
Ok...well guys, whatever works for you.
I still think you are wearing garters, not that there is anything wrong with that....
If you believe in it.....hey, do it.
I still think you are wearing garters, not that there is anything wrong with that....
If you believe in it.....hey, do it.
D
Deleted member 10043
Guest
Simple we all shoot at the same rifle ranges that were designed to face the most likely avenue of approach.
Are you trolling?
In case you're not, i want to be able to shoot someone peeking out a window or over a wall (most common sight of someone fighting you) and knowing the fine details of my zero helps me with that.
I work with both of those carbines all the time so I guess I’m getting lucky every time I shoot 36/300 to confirm both zeros. Honestly, Luck has nothing to do with it, given my 300 yard target is usually one of my 2/3 ipsc steel targets. The zero does work assuming a man-sized Target , either with 55g XM193 or 77g mk262 mod 1 or my Mo262 M1 clone load. I don’t use or shoot any other bullets beyond the 55g, 62g or 77g in any of my ARs. My only goal with them is to place rounds center mass, not as concerned about maintaining 1 MOA like I would with a precision system.
I suppose if different bullets and loads were used and/or the target was much smaller, I’d come across some that don’t work as well where I would have to zero at 300 and know my holds at 36. But it’s much more likely I’m engaging at a distance much closer to 36 then at 300 anyway.
Perhaps another consideration is my environment itself. My D/A is typically 4800 (winter) to 6600 (spring/summer/fall) so rounds may be flying fast enough to offset the need to adjust whereas at sea level, I would need to adjust to put the round on target at 300 using the 36 yard poa=poi.
You're missing the point, and it's working for you because you're definition of a "zero" is apparently pretty loose, if it just means ringing the steel. That's not "zeroed" necessarily, it's just "close enough".
The different loads you mentioned have different trajectories and different poi at any significant distance. If you've zeroed them at 36 yds, they obviously can't all be zeroed at 300 yards as well, right? The trajectories don't fit. Talking about actual zero, not just close enough to bang a steel plate. I think you got lucky by zeroing something close enough to get your different rounds on target at 300, but your actual true near zero is not really at 36 yds, but something closer or farther.
Last edited:
I'm not sure if you're asking me, since you "liked" my previous post on the subject above so you know we're on the same page there. My comments are directed to the guys who just zero at 36 yards and assume that they're also zeroed at 300 - they're not. They might be on paper/steel at 300, but again maybe not, and the only way to know is to actually shoot to verify. IMO this "36/300" thing is mostly accepted by guys who zero at 36 and never shoot much farther than about 50 yards, from what I've observed. Obviously some exceptions exist.
Personally the only time I'm using a 300 yd zero is when my scope is dialed to 300 yds. For red dot carbines/pistols I'm zeroed closer and am naturally holding over at extended ranges instead of this MPBR thing that only works to a certain distance.
Yes it’s more of a “close enough” vs hitting the exact same spot via a dialed solution on a scope (ie an actual zero) each and every time. With a more precision oriented rig, I’d have such a zero at distances between 100-300 but it’s a cqb weapon so I prioritize speed and shot placement close in because a preponderance of shots are taken at targets at those shorter distances. If I can also place rounds on target at 300 without thinking or dialing (just point and shoot) I’m good with that for those carbines.
My point was I didn’t have to adjust to hit but to your point, I didn’t specifically adjust the elevation or windage at 300, I did so at 36. The ballistics of the round allows for the 36 yard zero to also work at 300 poa equaling poi. I regularly take all my systems to distance to validate the rifle and loads work and that the dope is also currently valid.
It's like you're intentionally missing the point here. The trajectory of the different rounds you mentioned are not the same; not everything coming out the muzzle of an AR matches a 36/300 yd zero, especially from shorter barrel lengths. If zeroed at 300, they'll be close enough at 36 yds that most will call it zeroed, but if actually zeroed at 36 yards a lot of setups will be way off at 300. I know some of you guys don't handle numbers and ballistics well, but this should be pretty evident to most.
You may have started at 36 yds, but you at least confirmed at 300 and presumably would have adjusted if you weren't on target. Lots of guys using this 36/300 method don't. How is that so hard to understand?
Here's another one - if your priority is speed and shot placement in a torso, that can be done better and faster if you're actually zeroed where you think you are. Just saying "good enough" when you're ringing the edge of the steel at 300 doesn't make you faster on target. Confirming you're hitting center at 300 (or whatever your magic zero is) makes your hits more repeatable with the potential to be faster. When guys don't bother to even confirm their far zero, regardless what the range is, they're not faster on target, they may not hit the target at all.
Again, I've seen guys here asking about using this method for 300 Blk, 7.62x39 Aks, SBR 5.56 and Grendels, etc; all stuff that doesn't fit the 36/300 yd thing at all, but the dumbed down idea of "just zero at 36 yards" thing gets repeated and doesn't do those guys any favors at all.
Relying on the near zero only and neglecting the far zero is never better, it's just lazy. That is my point.
Last edited:
I can’t speak to why other people don’t confirm their presumed dope further down range, don’t really care about their reasons for not doing so. When I do my part those rounds consistently hit high-center at 300 when holding on the center of target...And of course the trajectories are different for each round; most anyone, at least on this site would know that. I have no problem understanding numbers & ballistics so you obviously aren’t referring to me with that comment.
That said, their respective trajectories are not so radically different out of a typical 14.5 to 16” AR that any significant adjustments are required to get on target center mass at 300 with a 2/3 ipsc or full Ipsc center mass for a shooter using a 36 yard zero.
I know, unfortunately it’s just about the only credit card I’ll be hittin for quite a while, lol.
He's not really talking DOPE (POA = POI) at all. His desired end-state is to miss 6" or less out to 300y...which he's defined as good enough. He's a door-kicker. Ok, fine, if you're setting up a door-kicker carbine, and are willing to trade larger miss distance inside 150y, for smaller miss distance from 200-300y, ok.
Just know what you're trading.
Ugh. I'm trying to determine the significance being placed on 300y. Per your response, you expect someone to be peeking out at 300y? What if they're peeking out at 280, or 320, or 247y?
The guy that sets his rifle up to minute-of-dvd is likely not successfully engaging a peeking individual at those ranges. He's calling the DM or sniper...who has a 100y zero and knows his DOPE for everything else. That's what most on this site (Sniper's Hide) should be doing...as it would be a rare event someone here would find themselves in a scenario that involves engaging a target at 250+ WITHOUT the time to range and use DOPE.
Again, why the significance placed on 300y zero?
Wow talk about going balls deep into the weeds when you don’t need to.
If you don’t have access to a range farther than 100yds, you aren’t going to see a real difference between zeros because you won’t be able to confirm the offsets. If you do have access, then the zero type still doesn’t matter because you’re able to actually measure the exact offset at your varying differences. Once you know your offset, it’s just a number/reference you need to memorize and train with. There’s no difference between knowing that you have a 3” offset at ____yds and knowing that you have to hold 3.2 mils at ____yds on your precision rifle. DOPE is DOPE guys, that concept doesn’t change between systems or target type.
The discussion isn’t “hey I’m re-writing my unit/department SOPs and I need to know what’s the best zero that I can pitch while citing previous incidents.” which means you aren’t working inside of a constrained box.
Grab some targets and get to experimenting. See what works best for your system/ammo combination and then put em to the test on paper. Paper doesn’t lie and you’ll quickly find where your limits (be it ammo/rifle/optic/shooter ability) are as well as which method works best with the way you overlay your sights on a target.
Whatever performs the best for you is the zero you should train with. That’s the only right answer.
PS: Forget that I said 36/300 is the way to go. The 27.9m/406yd zero is the best when running 43gr +P+ FMJAPSMKBTHP 5.56.
If you don’t have access to a range farther than 100yds, you aren’t going to see a real difference between zeros because you won’t be able to confirm the offsets. If you do have access, then the zero type still doesn’t matter because you’re able to actually measure the exact offset at your varying differences. Once you know your offset, it’s just a number/reference you need to memorize and train with. There’s no difference between knowing that you have a 3” offset at ____yds and knowing that you have to hold 3.2 mils at ____yds on your precision rifle. DOPE is DOPE guys, that concept doesn’t change between systems or target type.
The discussion isn’t “hey I’m re-writing my unit/department SOPs and I need to know what’s the best zero that I can pitch while citing previous incidents.” which means you aren’t working inside of a constrained box.
Grab some targets and get to experimenting. See what works best for your system/ammo combination and then put em to the test on paper. Paper doesn’t lie and you’ll quickly find where your limits (be it ammo/rifle/optic/shooter ability) are as well as which method works best with the way you overlay your sights on a target.
Whatever performs the best for you is the zero you should train with. That’s the only right answer.
PS: Forget that I said 36/300 is the way to go. The 27.9m/406yd zero is the best when running 43gr +P+ FMJAPSMKBTHP 5.56.
Not sure how saying a 100y zero + DOPE is balls deep.
And I think your PS made my point. 300y zero is as dumb as 406y zero.
The SEAL in the video isn't using 3" offset at x range either....he's saying he's ok w/ the error all the way to 300y. That's not the same argument you're making.
And I think your PS made my point. 300y zero is as dumb as 406y zero.
The SEAL in the video isn't using 3" offset at x range either....he's saying he's ok w/ the error all the way to 300y. That's not the same argument you're making.
Last edited:
No I'm referring to everyone going as deep as they have for this discussion, as until they confirm it, its all try data. The point of my sarcastic PS is that none of them matter unless you confirm your offsets and actually apply them. 300 is just as useless as 200 and 100 if you don't actually confirm it. I get what the seal dude is saying, it isn't complex nor was that what I meant. Zero your rifle the way you want to and measure your offsets. If the POA/POI spread is acceptable to you, then run it. If it isn't and you don't want to think (even though it shouldn't require you to do so) then change your zero or apply the offset. Shit, a 5" spread out to 300 is perfectly acceptable and useable in reality. A dude who knows and trains his holds (regardless of zero) will always be better than the guy that picked ____ BZO over ____ BZO and never confirms it. That's the point I'm making. Know your system and it won't matter what zero you go with.
This is the same kind of nonsense that goes on for 100 options regarding at what distance an RMR should be zeroed on a pistol. Try em all and use what works best for you.... But seriously gents, we should give the 15yd/500m BZO a solid look over.
Copy, and concur. Knowing your setup is key.
Points I was trying to make for the above posters were:
- tweaking your 36y zero to be on at 300y...sure, it means you're on at 300y (if you can really determine that w/ a carbine)...but the act of readjusting zero at 300y isn't what the original goal was...which was to have an acceptable error from x yards to x yards.
- that using a 100y zero + knowing your DOPE (which is what you're saying above...go shoot, learn your POI) will work better for the majority here. Then you have a smaller error inside 200y, they're all hold-overs, and the whole system concept works like every other rifle they likely have.
I'm a fan of zeroing at the point where you have a single zero. (i.e., never have hold-unders). For centerfire, 100y normally works. Rimfire, it's around 38y.
This keeps things simple (and fast...which was one of the original arguments of this thread), and minimizes the rate of change from POA to POI over the course of the trajectory.
To each his own obviously, just sharing thoughts. I've learned a ton on here in 10 years, and continue to do so every day.
S/F.
Points I was trying to make for the above posters were:
- tweaking your 36y zero to be on at 300y...sure, it means you're on at 300y (if you can really determine that w/ a carbine)...but the act of readjusting zero at 300y isn't what the original goal was...which was to have an acceptable error from x yards to x yards.
- that using a 100y zero + knowing your DOPE (which is what you're saying above...go shoot, learn your POI) will work better for the majority here. Then you have a smaller error inside 200y, they're all hold-overs, and the whole system concept works like every other rifle they likely have.
I'm a fan of zeroing at the point where you have a single zero. (i.e., never have hold-unders). For centerfire, 100y normally works. Rimfire, it's around 38y.
This keeps things simple (and fast...which was one of the original arguments of this thread), and minimizes the rate of change from POA to POI over the course of the trajectory.
To each his own obviously, just sharing thoughts. I've learned a ton on here in 10 years, and continue to do so every day.
S/F.
Last edited:
I noticed you have scope height set for 1.5”, which I’m guessing Is the height of the mount you’re using (pretty standard height). Don’t forget to include the 1.2” from the center of bore to top of receiver for an AR. So, the scope height over bore would be 2.7”.
Not really.
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.)
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.
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.
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 zeroing scheme 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.
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 zeroing scheme based on the pertinent facts.
Now, let’s add the 36 yard zero into the mix.
From the muzzle to approximately 42 yards, the 36 yard zero has a slight advantage over the 50 yard zero. From 50 yards out to approximately 235 yards, the 50 yard zero has a distinct advantage over the 36 yards zero. It isn’t until shooting past the distance of approximately 235 yards that the 36 yard zero regains any advantage over the 50 yard zero.
….
Last edited:
How exactly are you going to "hold at the belt buckle area . . . and belly button area" in any type of realistic scenario where the tango is shooting at you from behind hard cover or while in defilade position?
....
ETA: Beat by Molon. Funny how we were saying the same thing.
I’ve never seen 36/300 match up before, and recall going through all this back in the early 2000s, but I just ran the ballistics through a calculator again just as a sanity check.
Army JSOC had this all worked-out back then, and the few guys from there that talk about it frown on 36/300yd. They prefer a 50yd zero for the following reasons...
Problem with 300yd zeros is that they put trajectory over people’s heads in the more common distances, and you can see this clearly in the video in the OP. He has the POI references drawn on the IPSC. At 5:06 in the video, look at the 36yd zero Points of Impact for 50, 100, 150, and 200. Everything you need to know is clearly illustrated right there in that frame. If you’re shooting IPSC sils perfectly oriented towards you, sure. Great zero.
But if you’re shooting through partially-exposed heads peeking around a corner, 36yd zero is one of the worst zeros you could use, only outdone by the 25m zero.
Just think of the IPSC steel with hostage taker as someone peeking from cover, not necessarily a hostage situation for the purpose of this argument (although even more relevant for LEOs) PRETEND the SIL is a barrier for sake of this argument, the red head is the intended target:
Factor in:
Size of TGT (never going to be full IPSC standing in presentation towards you, “shoot me please")
Cone of error of rifle/optic combo (2-4 MOA mechanical best case)
Cone of error for shooting under stress from field expedient position (accuracy degrades by 50% under stress among the world’s best combat shooters)
14.5” 5.56 M855 or 62gr .306 G1 BC, 2920fps mv, 36yd zero, 2.5” optic height
(These are perfect world POI trajectories without any cone of error or positional error factors.)
50 .8” high
75 2” high
100 3” high
125 3.6” high
150 3.8” high
175 3.8” high
200 3.3” high
225 2.5” high
250 1.2” high
275 - .5” low (this is the first time along the flight path since 36yd that we have any drop)
300 - 2.7” low
Same gun, same ammo, 50yd zero
50 ZERO
75 .8” high
100 1.3” high
125 1.5” high
150 1.4” high
175 .9” high
200 ZERO
225 -1.2"
250 -2.9"
275 -5"
300 - 7.6"
For these reasons, I’m not a fan of the 36yd zero. It’s already hard enough to make hits, so why make it even more difficult? I didn’t take anyone’s word or credentials at face value and just accept their recommendations, but instead analyzed the data for myself with all variables accounted for, and could clearly see that the 36yd zero decreases your chances of hitting partially-exposed targets within the common engagement distances in urban and open terrain.
I’ve never seen 36/300 match up before, and recall going through all this back in the early 2000s, but I just ran the ballistics through a calculator again just as a sanity check.
Army JSOC had this all worked-out back then, and the few guys from there that talk about it frown on 36/300yd. They prefer a 50yd zero for the following reasons...
Problem with 300yd zeros is that they put trajectory over people’s heads in the more common distances, and you can see this clearly in the video in the OP. He has the POI references drawn on the IPSC. At 5:06 in the video, look at the 36yd zero Points of Impact for 50, 100, 150, and 200. Everything you need to know is clearly illustrated right there in that frame. If you’re shooting IPSC sils perfectly oriented towards you, sure. Great zero.
But if you’re shooting through partially-exposed heads peeking around a corner, 36yd zero is one of the worst zeros you could use, only outdone by the 25m zero.
Just think of the IPSC steel with hostage taker as someone peeking from cover, not necessarily a hostage situation for the purpose of this argument (although even more relevant for LEOs) PRETEND the SIL is a barrier for sake of this argument, the red head is the intended target:
Factor in:
Size of TGT (never going to be full IPSC standing in presentation towards you, “shoot me please")
Cone of error of rifle/optic combo (2-4 MOA mechanical best case)
Cone of error for shooting under stress from field expedient position (accuracy degrades by 50% under stress among the world’s best combat shooters)
14.5” 5.56 M855 or 62gr .306 G1 BC, 2920fps mv, 36yd zero, 2.5” optic height
(These are perfect world POI trajectories without any cone of error or positional error factors.)
50 .8” high
75 2” high
100 3” high
125 3.6” high
150 3.8” high
175 3.8” high
200 3.3” high
225 2.5” high
250 1.2” high
275 - .5” low (this is the first time along the flight path since 36yd that we have any drop)
300 - 2.7” low
Same gun, same ammo, 50yd zero
50 ZERO
75 .8” high
100 1.3” high
125 1.5” high
150 1.4” high
175 .9” high
200 ZERO
225 -1.2"
250 -2.9"
275 -5"
300 - 7.6"
For these reasons, I’m not a fan of the 36yd zero. It’s already hard enough to make hits, so why make it even more difficult? I didn’t take anyone’s word or credentials at face value and just accept their recommendations, but instead analyzed the data for myself with all variables accounted for, and could clearly see that the 36yd zero decreases your chances of hitting partially-exposed targets within the common engagement distances in urban and open terrain.
Last edited:
