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Thread: The Battlefield Zero

  1. #1
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    Default The Battlefield Zero

    This is a recreation of Paul Howe's excellent article on carbine zero's, it has been transformed to make it easier to load/ read on a forum. It is hosted here with his permission. The original file is available for download here, complete with full resolution pictures:
    http://www.combatshootingandtactics....llpictures.pdf



    The Battlefield Zero
    By Paul Howe


    General
    I have heard many explanations and thought processes as to the best "Battlefield Zero"
    for the M16/M-4 type weapon system. Some explain how the knobs should be turned and
    the sights flipped to best accommodate hits. Some of these explanations require a college
    degree to decipher. Others use graphs and charts to justify their claims. Nothing confirms
    a zero like walking the actual ground and checking the hits on your target. So put away
    your graphs, charts, knobs, etc. and let's look at some holds and shots.
    For the record, I zero at 100 yards….

    Weapon and Ammo:
    Rifle: Rock River
    Sights: Iron (CSAT Rear/Trijicon Front with tritium insert)
    Ammo: 62 Grain American Eagle FMJ/55 Grain WW FMJ
    Wind: Day 1 Gusting/Variable from L-R/Day two was calm
    Position used: Prone Unsupported
    Rifle Used: Rock River


    I make a box using the head template, roughly 6 x 6 inches. I put it high in the scoring
    box of a CSAT target to get a high thoracic hit.



    DELIBERATE OFFSET OF 3" HIGH WITH MY SIGHTS:
    At 100 yards, I adjusted my sights to hit about 3" high or 3 click up on my rear dial
    from where my front sight cut the target. 100 Yard hit are marked in the center of
    the box.
    - 75 hit a little lower
    - 50 a little lower
    - 25 cut the line



    100 Yard Point of Aim/Point of Impact


    My zero here was to have the bullets cut where my front sight post met the target. The
    group dropped a little lower than the offset method from 100 yards and in. No real
    change in overall group.



    3"OFFSET AT 200/300

    Here is where the real difference can be found in the zeros. Out to 200 yards, you
    hit about the same. At 300, you drop from 4 to 12". Remember, this is the built in
    offset and my sight picture was consistent at the base of the box.



    POA/POI at 100 caused me minor problems at 200/300. It dropped a bit more at
    200 and 300 was significantly low. Normally I hold on your shoulders or face when
    shooting 300 with this zero.
    Also, my eye was getting fuzzy by this time, trying to see the small box. It was fading
    out at times.

    Head Shots:



    Head Shots at 100 with the offset was easy to see and deliver



    POA/POI works, but I threw one. As a side note, you can do a center hold, but your
    eye may have a problem going back and forth to see how much black you are
    dipping your sight into. This may cause eye strain. Using a 6 o'clock hold, you can
    simply lollypop the head on your front sight.

    OVERALL RESULTS:
    Deliberate Offset Method (3" high at 100 yards)

    - The deliberate offset method gave me reliable hits out to 300 with the same sight
    picture.
    - At 100 on a head target, I would simply hold on your chin and get a center mass
    hit in your melon. If you were prone, I would simply aim where your head and
    ground meet.

    Point of Aim/Point of Impact Method

    - Gives you accurate hits to 100-200 yards
    - Falls off at 300
    - At 300, I know to hold on the shoulders

    OTHER POINTS:
    100 zero

    I prefer zeroing and training at 100 yards for several reasons:
    - It makes you a better shooter
    - It is a realistic distance for combat and the capability of your weapon
    - It gives you a versatile zero out to 300 yards with a realistic expectation of a 1st
    round hit.

    As a side note, I have never had anyone come to a Tactical Rifle Instructor or Tactical
    Rifle course with a 50 yard zero and shoot it across my standards or ranges. All had to
    adjust their sights. Many did not know where their round would strike at 100 and
    beyond.

    Field Fire

    I first picked up this term in my time as a sniper. That is having a zero and knowing your
    hold offs for targets within the appropriate range of your weapon. This is important to
    know for combat.

    Sights



    You need to learn how to shoot iron sights. Above is a picture of an Aimpoint T-1 that
    was hit with a simunitions round during training. This could have just as easy been a
    bullet, shrapnel, debris, mud, etc. You need a quick release mount when using optics and
    I suggest that you co-witness them with your iron sights. Reference optics, my favorites
    are the Leupold CQT and the Aimpoint T-1.

    Establishing reference points for consistent shooting is critical for consistent accuracy.
    These "index" points will transfer to weapons with optical sights.

    I have witnessed optics fail in competitions, training and combat. In one law
    enforcement situation, a battery powered optic failed and the officer killed a bad guy with
    his iron sights five minutes later. In combat I have witnessed soldiers with optics that
    clouded up with moisture have to pick up a new weapon because they could not get the
    optic off and could not see through it.

    It is criminal that the U.S. Army is teaching basic training recruits to shoot with
    Aimpoints and no iron sights. They are going to get soldiers killed or other Army units
    will have to retrain them sometime down the road.



    I have developed a combat sight that allows you to shoot 0-300 yards and beyond if you
    know your weapon system. In the above sight, you use the notch at 7 yards and the peep
    beyond 15. I try to keep it simple.

    Also, I mark my windage and elevation knobs with a paint pen to know where my zero is.
    I can view these marks as part of my pre-combat inspection of my rifle.

    Sight Radius
    The sight radius on your weapon does have a significant impact on your weapons zero,
    no pun intended.



    The top weapon has a mid-length hand guard and about two-inches more sight radius. I
    believe this additional sight radius helps the accuracy of iron sighted shooters.

    Some of the improved accuracy you find in the various M-4 weapon systems is due to
    barrel length, some is due to increased sight radius. I compare it to shooting a short
    barreled revolver. In the past, some agencies required officers to shoot 50 yards courses
    of fire with a snub nosed revolver. Many did it. What it took was many hours of practice
    and the officer doing the same thing every time when behind the gun. An officer with
    less trigger time and experience could make the same hits with less training time by using
    a longer sight radius on a four or six inch barreled revolver. The sight radius of these
    guns would help them out. The same applies to rifles

    Zero's and Results

    Through these series of pictures, I am attempting to show how I zero and my groups out
    to 300 yards using iron sights. I hope I have simplified your understanding of this
    process. There is little magic to it and it works.



    The above groups were fired using WW 55 grain FMJ. The top group was using my
    AE 62 Grain zero from the day before. I had to come down four clicks and left four
    clicks on my rear drums to get my groups to center up.
    - If you change ammo weights or manufacturers, re-check your zero. It will
    change your zero.



    The above group was fired using WW 55 Grain FMJ using the 100 yard 3" offset on
    the sights. My 300 yard group was a bit spread out because I was taking too much
    time going back and forth with my eye to the target and the sight, trying to fine tune
    the shot.



    This group was fired using POA/POI WW 55 Grain FMJ. I threw one out a bit at
    200, but I am happy with my 300 yard group. In this string, I took my first best
    sight picture and pulled the trigger without trying to over focus on the target.
    Generally, your bullet drops two" inches at 200. Your eye cannot see this.

    Summary:
    I do occasionally shoot optics and have some that I like and us. When I do shoot them, I
    have them co-witnessed and mounted with throw lever mounts whenever possible should
    they fail.

    In my experience of fast moving combat, I never had time to turn knobs or flip sights. I
    had to use what I had on the gun for the shot required. The window of opportunity opens
    and closes in a flash and you either make the shot or you do not. You might have time in
    a static position such as was found in WWII, but not in a fast moving urban environment.
    Further, you now have a light caliber weapon system that requires more accurate hits to
    put the target down in a rapid manner. In this case, you must know where your bullet
    strikes to do this.

    Finally, in my former special operations life I learned that you might get a full body shot
    on one opponent in a gun fight, but as soon as you shoot them, their friends will take
    cover and probably only give you a head or weapon system to shoot at. I used to make
    team members practice shots on full and partial targets at 100 yards and beyond. This is
    reality. Bad guys use cover as we do. You must be able to hit them when they get small.
    I hope this helps answer some questions and if you have any, feel free to e-mail me via
    my web site.

    About the Author
    Paul R. Howe is a 20-year veteran and former Special Operations soldier and instructor.
    Paul currently owns Combat Shooting and Tactics (CSAT) where he consults with, trains
    and evaluates law enforcement and government agencies in technical and tactical
    techniques throughout the special operations spectrum. See
    http://www.combatshootingandtactics.com for details.

  2. #2
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    Default Some video on zeroing your carbine


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    Default

    Also, KD wrote up a nice article on rifle zeros.
    http://www.kyledefoor.com/2010/12/12-days-of-zero.html
    Therefore, he who wishes peace, should prepare war; he who desires victory, should carefully train his soldiers; he who wants favorable results, should fight relying on skill, not on chance.

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    Default

    Quote Originally Posted by Jim D View Post
    Also, KD wrote up a nice article on rifle zeros.
    http://www.kyledefoor.com/2010/12/12-days-of-zero.html
    He did a very good job, to the point of making me reconsider the 100 yard zero.

  5. Default

    Quote Originally Posted by Jim D View Post
    Also, KD wrote up a nice article on rifle zeros.
    http://www.kyledefoor.com/2010/12/12-days-of-zero.html

    Kyle did some great data collection/observations for that article. The 100 yd zero is a great zero when there are certain constraints (e.g., time, skill set, range, lack of config info for the platform being run). You know I was a HUGE advocate of the 100yd zero and it still makes a lot of sense for room distance out to common engagement distances (50 - 75 yds).

    Plus if you don't have a range with more than 100 yds it's tough to truly do any other kind of zero because you can't confirm second intersect. Another reason "round numbered" zeros are good is when you need to get a bunch of folks, using different gear, at different skill levels, sighted in pretty quickly (e.g., start of a class, large LE/Mil units).

    But, if you've got 300 yds (if you're shooting .223/5.56), a ballistics calc, a tape measure, chrono, bullet specs, and a day to spend at the range then I believe the 4" MPBR zero is the way to go. Here's how it was explained to me and it makes a lot of sense which is why we now all run MPBR -

    If guys are saying they're getting (at most) 3-secs of exposure from a bad guy at unknown distance between 100 - 250 yds and once rounds have been fired they're only exposing some of their head then the 100 yd zero brings some additional, and unnecessary, variables to the table. If we're getting 3-sec exposure then in that time we have to estimate distance and make a hold on a 4" target. That's tough.

    Where as with MPBR in the same situation (out in some cases to 270+ yds with 55 Gr 5.56) the dot/reticle is placed on the center of his face and you'll get the hit. No figuring out holds (unless target is beyond your MPBR). Basically, compared to 100 yd zero, MPBR adds a shit-load of usable distance before you need to start working out holds.

    Anyway, just throwing an option out there, without a doubt there's way more to zeroing MPBR but I think it's worth it.

    Best,
    HD

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    Quote Originally Posted by Jim D View Post


    You need to learn how to shoot iron sights. Above is a picture of an Aimpoint T-1 that
    was hit with a simunitions round during training. This could have just as easy been a
    bullet, shrapnel, debris, mud, etc. You need a quick release mount when using optics and
    I suggest that you co-witness them with your iron sights. Reference optics, my favorites
    are the Leupold CQT and the Aimpoint T-1.

    Establishing reference points for consistent shooting is critical for consistent accuracy.
    These "index" points will transfer to weapons with optical sights.

    I have witnessed optics fail in competitions, training and combat. In one law
    enforcement situation, a battery powered optic failed and the officer killed a bad guy with
    his iron sights five minutes later. In combat I have witnessed soldiers with optics that
    clouded up with moisture have to pick up a new weapon because they could not get the
    optic off and could not see through it.
    I have seen the above before and think it's very important and often overlooked. Your Aimpoint might not just be dead because the batteries ran down, it could have been hit by a round or shrapnel or it could have been smacked really hard against a hard surface. You need to be able to see through the optic to use the irons. If you can't you need to be able to get it off. I currently recommend the LaRue or the ADM mounts - the KAC may also be GTG but I am not personally familiar with it.
    Arm Yourself With Knowledge

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    Default

    Quote Originally Posted by DEERHUNTER1-8 View Post
    Kyle did some great data collection/observations for that article. The 100 yd zero is a great zero when there are certain constraints (e.g., time, skill set, range, lack of config info for the platform being run). You know I was a HUGE advocate of the 100yd zero and it still makes a lot of sense for room distance out to common engagement distances (50 - 75 yds).

    Plus if you don't have a range with more than 100 yds it's tough to truly do any other kind of zero because you can't confirm second intersect. Another reason "round numbered" zeros are good is when you need to get a bunch of folks, using different gear, at different skill levels, sighted in pretty quickly (e.g., start of a class, large LE/Mil units).

    But, if you've got 300 yds (if you're shooting .223/5.56), a ballistics calc, a tape measure, chrono, bullet specs, and a day to spend at the range then I believe the 4" MPBR zero is the way to go. Here's how it was explained to me and it makes a lot of sense which is why we now all run MPBR -

    If guys are saying they're getting (at most) 3-secs of exposure from a bad guy at unknown distance between 100 - 250 yds and once rounds have been fired they're only exposing some of their head then the 100 yd zero brings some additional, and unnecessary, variables to the table. If we're getting 3-sec exposure then in that time we have to estimate distance and make a hold on a 4" target. That's tough.

    Where as with MPBR in the same situation (out in some cases to 270+ yds with 55 Gr 5.56) the dot/reticle is placed on the center of his face and you'll get the hit. No figuring out holds (unless target is beyond your MPBR). Basically, compared to 100 yd zero, MPBR adds a shit-load of usable distance before you need to start working out holds.

    Anyway, just throwing an option out there, without a doubt there's way more to zeroing MPBR but I think it's worth it.

    Best,
    HD
    Can you give us a little more info on "MPBR" ?
    I understand it means Max Point Blank Range, but I just started to get into carbines this last year and am learning.

    Im running a 50/200 zero now. I have honestly no other reason except its what was suggested in 2 seperate courses I took from two seperate instructors and Im not having issues getting hits from inside 7 to 50, to 100, and I was knocking a steel plate (IIRC 8") at 250 inside a steel coyote at 250 shooting Wolf 62 grain ammo just the other week holding at the bottom of my 4MOA Aimpoint dot.

    If theres something better, Id like to try it out.
    Last edited by Shawn.L; 01-02-2011 at 18:19.
    Can you imagine what I would do if I could do all I can?
    ~Sun Tzu

  8. Default

    Quote Originally Posted by Shawn.L View Post
    Can you give us a little more info on "MPBR" ?
    I understand it means Max Point Blank Range, but I just started to get into carbines this last year and am learning.

    Im running a 50/200 zero now. I have honestly no other reason except its what was suggested in 2 seperate courses I took from two seperate instructors and Im not having issues getting hits from inside 7 to 50, to 100, and I was knocking a steel plate (IIRC 8") at 250 inside a steel coyote at 250 shooting Wolf 62 grain ammo just the other week holding at the bottom of my 4MOA Aimpoint dot.

    If theres something better, Id like to try it out.
    Hey Shawn -

    First, the 50/200 is a GREAT zero, it's what I run on rifles I don't have the time to setup MPBR on. 50/200 gives very similar trajectories to what MPBR would give you.

    Here's a link to a MPBR overview (if you're not on FB let me know and I'll post the text here): http://www.facebook.com/note.php?not...42604852421412

    Let me know if you have any questions once you've read the article . . . I'm sure you will, there's a lot to MPBR but we think it's worth doing for at least your primary rifle.

    Best,
    HKD
    virus Dei

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    Default

    im not on FB
    Can you imagine what I would do if I could do all I can?
    ~Sun Tzu

  10. #10

    Default

    I took the liberty to copy and paste from FB.

    Below is NOT ME.




    Introduction to Maximum Point Blank Range (MPBR) Zeroby Sayoc Tactical Group on Tuesday, July 13, 2010 at 10:13am
    MPBR, a brief explanation

    by Dave Affleck


    Since writing about the extended MPBR achieved with my .17 Predator and .20-250 projects, I’ve received a few emails and private messages lately asking for clarification regarding exactly what MPBR is and why I choose to use it. So I decided to put my answers into a short article to post here for future reference.

    MPBR stands for Maximum Point Blank Range. Simply put, MPBR is the furthest distance you can zero your rifle for, at which your bullet is never above or below your line of sight by more than a certain amount. The idea being that you can then aim at the center of the target from the muzzle to the MPBR distance without concern for holding over. The size of your intended target should determine the distance you decide to allow above or below your line of sight. For all of my varmint rifles, I use a target size of 4” to determine MPBR. So I zero my varmint rifles to have the bullet not rise to more than 2” above my line of sight. The point at which the bullet then drops to 2” below my line of sight is the MPBR for that rifle and that particular load.

    One description of the MPBR concept that has been used a lot over the years is to visualize shooting with your barrel centered inside an imaginary pipe. The target size determines the size of the pipe – in the case of all my varmint rifles it would be a 4” pipe. MPBR is the furthest distance at which a bullet fired from your rifle will stay inside the pipe without hitting the top or the bottom.

    Most ballistics software programs will calculate MPBR for any given bullet and velocity. If you don’t have your own ballistics software program, there are excellent calculators available to use for free at the JBM Ballistics website. To get the most accurate results from any ballistics calculator, it’s important to input the variables as precisely as possible. Aside from the obvious velocity and B.C. variables, one of the variables that will have the most effect on getting an accurate MPBR calculation is sight height – the distance between the centerline of the barrel and the centerline of the scope. Altitude above sea level is another variable that will have a measurable effect on the accuracy of the calculations. I have found that when all of the variables are input correctly into the software, these programs give very accurate results. But one should still go out and do some actual shooting to verify results, just to be sure.

    Below is a trajectory table to illustrate a MPBR zero. The example used is a .22-250, shooting a 50 gr. Vmax at 3700 fps. A typical example of a fairly flat shooting factory rifle. This table was calculated using the JBM calculator linked above.

    The MPBR for the above example is 284 yards, with a 246 yard zero. In other words, when the rifle is zeroed to be dead on at 246 yards, the bullet will never be more than 2” above or 2” below your line of sight clear out to 284 yards. And the bullet will be only 3 inches low at 300 yards. Essentially allowing one to hold the same point of aim on a coyote sized animal from the muzzle to 300 yards. As shown in the chart, to achieve this zero you could sight in to be 1.6 inches high at 100 yards. Again though, you should always test your longer range zero if possible.

    So, now we have defined what MPBR is and how to zero a rifle for MPBR. The next logical question, one I have received in emails, is “why use MPBR?”. I can only give the reasons that I use MPBR zeroes on all my rifles. But before I do, I want to point out that there is no right or wrong here. Many people simply don’t like to use MPBR zeroes, for their own reasons. That’s fine. People should use whatever zeroing system they are comfortable with, and that gives them the best results. I have been using the MPBR concept to zero my scoped rifles my whole life. Literally, every scoped rifle I have ever owned, since childhood, has been zeroed using the MPBR concept. That’s the way my Dad taught me to do it (and he’s been using MPBR on all his scoped rifles since the 1950’s). So, I’m just extremely comfortable with the system, and frankly I’ve just never experienced any of the potential problems associated with it that are occasionally reported. However, I have observed over the years that often when a guy who has been using a 100 yard zero for a long time, switches to a MPBR zero, he may have a tendency to shoot over the backs of animals. More than once, I’ve seen someone accustomed to using a 100 yard zero, struggling to get used to using a MPBR zero without shooting over. This is why I say that there is no right or wrong answer here, just use the zero that makes the most sense to you.

    But why do I choose to use the MPBR zeroing method on all my rifles? To me MPBR just makes too much sense not to use it. I’ll use the same example as above to try and explain; a .22-250 shooting a 50 gr. bullet at 3700 fps. If this rifle were zeroed to be “dead on” at 100 yards, then it would be hitting almost 2 inches low at only 200 yards and 8 inches low at 300 yards. Below is the same MPBR trajectory chart as above, plus a trajectory chart for the same rifle using a 100 yard zero.

    As you can see, both zeros keep the bullet within 2” of your line of sight out to about 200 yards. But as the range increases beyond 200 yards, the MPBR zero continues to keep the bullet within that same 2” of your line of sight for nearly another 100 yards. While the with the 100 yard zero the bullet drops below that 2” zone almost immediately beyond 200 yards and starts dropping like a rock from there.

    So with the 100 yard zero, at any distance beyond about 210 yards, the bullet is hitting more than 2” low of the aim point and some adjustment in aiming/sight picture (“hold over”) will have to be used in order to make a good hit. As the distance increases further, the bullet really starts to hitting lower and lower in a hurry. By the time the bullet gets out to about 300 yards, not only am I going to have to use hold over to make a good hit, but I better be pretty accurate in my range estimation and my hold over calculation to boot. Since the bullet is dropping so fast at that range, small errors in range estimation or hold over calculation can quickly result in large aiming errors. So, to make a clean kill on a coyote at say 270 yards, I’m going to have to make an accurate estimation of the range, make an accurate calculation of the needed hold over and then hold over accurately by the correct amount. Any error in any of these things and I’ve got a miss or worse, a bad hit. Sheesh… Sounds like a lot of totally unnecessary chances to screw things up to me! By contrast, using the MPBR zero for this same rifle, to make that same shot at 270 yards, all I do is hold the exact same sight picture that I would at any other distance between the muzzle and the MPBR or 284 yards. No thought process, range estimation, hold over calculation or accurate hold over aiming required. Rather, just point and shoot, same as every other shot. Increase the distance just slightly more, to 300 yards, and the factors of range and hold over estimation become so critical with a 100 yard zero that a 25 yard range estimation error will result in the bullet hitting well off from the intended mark. Using the MPBR zero, on a 300 yard shot, the bullet is only impacting 3 inches low – if you guessed off by 25 yards either way, you are still likely to score a good hit.

    So, to me, it just doesn’t make any sense to take a flat shooting rifle like a .22-250, and then zero it dead on for 100 yards, and therefore have to worry about all that junk like range estimation and hold over starting at only 200 yards. When I could just use the MPBR zero instead, and simply not worry about exact range or holding over on any coyotes within the MPBR distance – which is 95% of all the coyotes I ever shoot at. This becomes even more of a no-brainer when dealing with really flat shooting cartridges like the .17 Predator or .20-250 which have MPBR’s of 350 yards or more on 4” targets. To me, using a 100 yard zero on a rifle like this is like buying a Corvette and putting a speed limiter on it to prevent going over 65 MPH.

    But, like I said earlier, to each his own! I’m really not out to try and convince anyone to change zeroing method. If you are a shooter that prefers a 100 yard zero, and it works for you, then more power to you! Use what you are comfortable with and what gives you the results you desire. For me though, that always has been and is always going to be the MPBR zero.

    - Dave Affleck
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