Very technical M4 vs. M16 question

Discussion in 'The Powder Keg' started by milproakron, Mar 31, 2009.

  1. milproakron

    milproakron G&G Newbie

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    Ok, so this is my dilemma: In my unit we have some really bad shooters. LoL really bad. But, due to budget constraints and just normal military red-tape, I can't get them the range time and personal attention they need to improve. I've kind of adopted a couple of them as a pet project.

    So, I want to take them out with MY M4'gery and teach them how to be better shooters. So the question becomes one of trajectory and impact point.

    My AR15 has the 16" barrel as opposed to the standard M16 20" barrel. I know the sight radius is different, but the sight picture is the same so that shouldn't be an issue. BUT, how about point of aim and point of impact regarding bullet trajectory between 25 meters and 300 meters. Does the 16" barrel make a difference? I've never really noticed a difference in my own experience, but I just want to make sure I'm not leaving anything out when I'm schooling them on marksmanship.

    For instance, zero at 25m gives you basically the same impact point at 250m with a standard M16. Does that change with the shorter barrel at those ranges? Any techy input would be appreciated. I'm just trying to help these soldiers out but I want to make sure my info is precise.
  2. jerry

    jerry G&G Evangelist Forum Contributor

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    If they are having issues, it most likely lies in breathing and trigger control.
    Fundamentals of Rifle Shooting
     Position and Technique-steady position and
    proper techniques for holding the rifle in all
    positions are the first fundamentals of shooting
     Aiming-sight alignment (aligning the front and
    rear sight) and sight picture (aiming point)
     Breath Control-it is important to know when and
    how long you need to hold your breath while firing
     Trigger Control-allows you to apply enough pressure on the trigger to fire the
    weapon without disturbing the sights

    I would get a bunch of 25 meter scaled silouette timed fired targets & let them go through the process of zeroing in then qualifying with this target at 25 meters Air Force Style) (simulates up to 300 meters) once they can qual on this I would let them take a crack at actual 300 meters (Army Style)
    [​IMG]

    Battle Sight Zero Rifle(s) and go from there

    M16A2 Mechanical and Battlesight Zeroing
    Mechanical zero is making adjustments to the sights of the rifle to give the
    shooter a good starting point. It should only be applied to weapons not
    previously zeroed or to newly assigned weapons
    Adjust the front sight up or down until the top of the sight post is 5mm above
    the machine surface of the front sight frame. Use cardstock with five lines, 1mm
    apart, to conduct mechanical zero
    Adjust the rear sight windage knob left or right until the normal range sight
    (unmarked aperture) is centered
    Turn the elevation knob down (CCW) until the rear sight is down to the last
    whole click. Before it bottoms out, turn it up (CW) until it is on the 8/3 mark on
    the range scale
    Battlesight zero starts out with a mechanically zeroed rifle using 5.56 mm ball
    ammunition. Adjust the sights for elevation and windage as needed
    For zeroing on a 25-meter range, turn the elevation knob one click past 8/3 on
    the range scale. After zero, set the elevation knob back to the 8/3 mark for
    actual target distances
    Once zero is complete, for target distance greater than 328 yd (300 m), place the
    correct range setting on the elevation knob to obtain the proper point of aim.
    On your mechanical zero cardstock, write down your battlesight zero for future
    reference
    Last edited: Mar 31, 2009
  3. Jersey Jailer

    Jersey Jailer G&G Newbie

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    When I had a problem shooter,in the academy, I would let them shoot at reactive targets, giving them immediate gratification. Targets were steel, fruits and vegetables(depending on time of year) bowling pins etc.. It was informal time on the range, just for fun. I found that it relaxed the student so they weren't under the gun to qualify. Of course we had to stress safety and we were able work on the basics. Of course it seemed that we always had a shooter that was cross dominant . The "fun" shoot always relaxed the shooter, so that they would listen to what we were trying to tell them during the formal training.
  4. Sprout47

    Sprout47 G&G Newbie

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    The difference is not that much, there is a loss of about 300 or so fps out the muzzle. I did find the m4 a little less accurate though. But if you take them out to the range and they can hit with that they will have no trouble hitting with the m16.

    Are you just intending on using the 25m range? if so then you really have nothing to worry about. I agree with the other posters, break them down and go over the marksmanship principals and beat it in their heads.

    They probably just don't have the experience, I mean mandated 2 times a year to the range really isn't enough time to get good at a weapon.
  5. milproakron

    milproakron G&G Newbie

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    Thanks guys. Yeah, I've been training people in marksmanship for alot of years, so they'll get the full treatment. I was just worried that if the trajectory was different they may get used to one way and find it different when they use their M16A2s. I'm hoping to have them shoot at targets smaller than the standard pop-ups as well.

    And you are absolutely right, Sprout47. That was the argument I laid out with HQ when I heard griping about the percentage of quals. 80 rounds per year does not a marksman make! LoL they are just kids. hell, they all are compared to me. I get pissed because HQs standard response is to just keep sending them to make up quals without providing them with any actual training to improve their shooting. If they get lucky enough to hit the right number of targets, everyone claps and goes home happy. Even if they all qualified, I'd still find it inadequate. Hitting 26 out of 40 targets wouldn't let me sleep much better at night. LoL
  6. milproakron

    milproakron G&G Newbie

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    Oh and Jerry, your point on mech zero:

    "M16A2 Mechanical and Battlesight Zeroing
    Mechanical zero is making adjustments to the sights of the rifle to give the
    shooter a good starting point. It should only be applied to weapons not
    previously zeroed or to newly assigned weapons
    Adjust the front sight up or down until the top of the sight post is 5mm above
    the machine surface of the front sight frame. Use cardstock with five lines, 1mm
    apart, to conduct mechanical zero
    Adjust the rear sight windage knob left or right until the normal range sight
    (unmarked aperture) is centered
    Turn the elevation knob down (CCW) until the rear sight is down to the last
    whole click. Before it bottoms out, turn it up (CW) until it is on the 8/3 mark on
    the range scale"


    I threw a fit about this because they received some new rifles and reassigned ALL of the rifles in the armory. Everyone was given a different rifle than the one they used for the last one, most for at least 2 years. They didn't know that until they were drawing weapons to head to the range. NONE had been placed back to mechanical zero prior to this. I bitched out the armorer and supply SGT for this oversight.

    "What's the big deal? They have to zero anyway." was the reply I got. Since you only get 18 rounds max to zero before you are SOL on your quals, adjusting a rifle already set up for someone else's battlesight zero can be difficult and can require more than 18 rounds. I fixed several on their way out to zero, but only a handful. There are just too damned many idiot NCOs who don't care about their troops anymore. At least here in our local units. Pathetic.

    and sad.
  7. Sprout47

    Sprout47 G&G Newbie

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    Anything less that 37 and im not sleeping, besides have to run to the px and get a different badge ;)
  8. toolman

    toolman Resident Sasquatch Forum Contributor

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    I can't say for sure one the 5.56 round, but the decrease in velocity from the shorter barrel will affect the trajectory at longer ranges. My ballistics program is AWOL at the moment, but when I get it loaded back up I'll post the expected differences.
  9. SwedeSteve

    SwedeSteve Freedom Zealot Forum Contributor

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    I see a few things to consider, with most already mentioned:

    Obtain a mechanical zero.
    Practice dime/washer
    Shoot one round and critique position and stock weld.
    Shoot another and critique breathing.
    Repeat 3 times.
    Put a 3 round group down range and critique.
    Repeat.
    Zero.

    "If short on rounds"
    Move target out to 100m.
    Tell them they have 12 rounds.
    Tell them Ivan will kill them in 3.
    They'll get to 2 in a heartbeat !!
    Been there done that !!
  10. mx308250

    mx308250 G&G Newbie

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    In our armory we de-issue the weapons as they are turned in, and re-issue different ones at every range. I'm not sure about the army, but Marine Corps order states that if you keep a weapon issued to you then it muse be cleaned by YOU once a month. All of the other weapons that are not isssued are to be cleaned by a working party once per month. The issue falls back on the individual that keeps it issued not coming to the armory to clean and then when CGI or some other inspection happens the armory fails.

    At each and every one of our ranges even if YOU used the same weapon last range, all the coaches set ALL of them to mechanical zero, front sight post flush, rear sight centered 8/3, then BZO them at 36 yards. Same point of impact at 300. Start pre-qual the next day at 200, 300 then 500, then the third day qualify 200, 300, 500. The next day go shoot table 2, tactical style shooting using 3 round burst for position refinement then one practice round then qualify.

    Seems to work every time for me, never had any problems. Only complaint I have is I am not used to ACOGs and wanted to rip mine off and use good ole carrying handle open sights for the tactical firing. Have not had the pleasure of cussing it on the long range yet.

    Some shooters require extra attention which does cause dilemmas. Sorry if I got a little off topic but it irratates me when people talk about how bad an armorer is for doing things a certain way. Just wanted to inform you of a possible reason why. :kiss:
  11. JOEYG707

    JOEYG707 G&G Newbie

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    Milpro, Only to second what MX said, is that my knowledge is from the USMC rifle marksmanship manual which states that the BZO is 36 or 300 yards where the bullet hits on its trajectory with the line of sight. Like i said my knowledge is from the manual being that im studying and practicing with my AR before i go in.


    CHEERS

    Attached Files:

  12. Sprout47

    Sprout47 G&G Newbie

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  13. milproakron

    milproakron G&G Newbie

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    I can appreciate your point of view and I appreciate the insight. BUT, LoL... Your example has nothing to do with the actions of our armory. This is a National Guard unit and neither of the armory occupants are acually MOS qualified armorers, small arms repair, or any other thing. It was just an idiotic idea the guy had the weekend before annual weapons quals. Believe me, I investigated and went through the entire chain of command. There was no hidden agenda or special purpose. He's just a moron.
  14. milproakron

    milproakron G&G Newbie

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    Thanks Joey. Yeah, my Army and Marine manuals show similar graphics, but unfortunately neither shows a different trajectory for M4 and M16. Not that I've found yet anyway. I'm sure the difference is negligible and a non-issue within 300 meters. I just like knowing for sure. lol
  15. Sprout47

    Sprout47 G&G Newbie

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    Just to shoot some basic numbers for you;

    62 Gr. M855 FMJ

    16" MV ='s 2952
    20" MV ='s 3117

    The numbers are pretty minimal. Judging from the different types of ammo the difference in MV is right around 100-200 FPS. Which, up to 500 meters breaks down to;

    3.28 ft/m

    500 meters is 1,640 feet, both barrel lengths are going to have a round out at that range in about .5 sec. At these speeds, the difference is truly minimal.

    If you want some science to wrap your head around... (which thanks by the way for making me drive myself nuts with this one).

    But I am thinking that since the rate at which the bullet drop doesn't change (constant of gravity), only thing that would change is where it drops. All things staying constant, 200 fps out the barrel means that for every second the rate of drop of the 20" will be 200 feet ahead of the 16", which should mean that at 1 second of flight on the same trajectory the 20" bullet at 3117 feet will be at the same position in space as the bullet fired from the 16" at 2952 feet.
  16. sea_chicken1

    sea_chicken1 G&G Enthusiast

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    what size target sould you use if you only have 25 to 30 meters to sight it in for 100?
  17. Sprout47

    Sprout47 G&G Newbie

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    You would use a 25m zero target and apply the following information:
    5.56 NATO Ball Ammunition Ballistic Comparison based on Aberdeen Proving Ground Data

    velocity (fps) trajectory (in.) drop (inches) drift (inches)*
    range(M) M193 M855 M193 M855 M193 M855 M193 M855

    0 3,200 3,100 -2.5 -2.5 0.0 0.0 0.0 0.0
    100 2,774 2,751 +2.8 +4.4 -2.2 -2.3 1.3 1.1
    200 2,374 2,420 +2.7 +5.8 -9.9 -10.2 5.8 4.9
    300 2,012 2,115 -4.9 0.0 -25.1 -25.3 14.2 11.8
    400 1,680 1,833 -23.0 -15.0 -50.8 -49.5 27.6 22.4
    500 1,373 1,569 -56.2 -42.9 -91.6 -86.7 47.5 38.0
    600 1,106 1,323 -113.1 -88.2 -156.1 -141.3 76.4 59.5
    700 995 1,106 -206.8 -156.1 -257.3 -220.9 113.5 88.4
    800 927 1,010 -339.9 -267.7 -398.0 -339.2 156.1 124.9

    * Drift for 10 mph wind.
    M193 Ball ammunition fired in M16A1 rifle with 250 meter battle sight zero.
    M855 Ball ammunition fired in M16A2 rifle with 300 meter battle sight zero.

    Goto http://www.ak-47.net/ammo/ss109.txt if it is a bit confusing here.
    Last edited: Apr 1, 2009
  18. jerry

    jerry G&G Evangelist Forum Contributor

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    This is off the target posted above. The ruler is 6" this target is used at 25M the silouhette is simulated 100 M.


    [​IMG]
    Last edited: Apr 2, 2009
  19. Soldier Medic

    Soldier Medic G&G Newbie

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    M-16 is more accurate than the M-4 hands down. the 5.56NATO round was originally tested with the M-16 and it worked very well. until the military came out with the Carbine M-4 with a 16.1" barrel, the NATO round lost some with those 4 inches. do i still hit 39 out of 40 when we switched over, YES!


    theres a current shooting program called NOCTAIL in the army that people do before they even go out and Zero. You should ask around for it through your chain of command, i think BLACKHAWK actually runs the program.

    Or you could just do what my supiriors do when the find themselves to busy to go out and shoot. They get me to shoot for them, they just give me thier firing card and they get at least a 35/40.
  20. sea_chicken1

    sea_chicken1 G&G Enthusiast

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    Thanks for the info on the zeroing I hate this area because theres no outdoor ranges around. I grew up shooting outside and indoor ranges still dont feel right.
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