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View Full Version : M16/M4 Minute of arc

Ofir
December 12, 2009, 06:03 AM
Can anyone tell me the MOA of Colt M16/M4 differences?

sneaky pete
December 12, 2009, 07:30 AM
old Sneaky Pete here: MOA is a Geometrical distance of deflection for a range that a minute(1) of angle makes--an example 1 MOA = 1.04719756 inches a 100 yards, at 200 yards 1 MOA =2.09439512 inches etc. this 1 MOA is usually rounded out to 1MOA=1 inch @ 100yds. This is usually applied to a specific bullet/projectile--an example, a .223/5/56 NATO round using a Sierra 55gr "Blitz-king" projectile has a BC( how slippery it flies thru the air) of .271 and the muzzle velocity(along with atmosphereic conditions) and other variable will determine how gravity and wind will effect the bullet path in MOA of deflection over a series of ranges. This is kind of a general overview of what happens when you pull the trigger.A good Reloading manual--I like the Sierra reloading manual, an excellent choice will give you a good overview on Ballistics and Trajectories. Sounds a little complicated at first but really isn't too hard to understand. I hope I didn't confuse you too much. THANX--SNEAKY :) P.S. Welcom to the "Club"--It becomes infecious--BUT remember "It's just the Inernet" and everyone has an Opinion

MEATSAW
December 12, 2009, 07:52 AM
So to clarify for everyone who is trying to learn something here: does the 1" at 100 yards mean that 1 MOA is equal to a circle with radius of 1" at 100 yards or is it equal to a circle with a diameter equal to 1"?

mavracer
December 12, 2009, 08:10 AM
So to clarify for everyone who is trying to learn something here: does the 1" at 100 yards mean that 1 MOA is equal to a circle with radius of 1" at 100 yards or is it equal to a circle with a diameter equal to 1"?
Since it's the base of the triangle it's a line not a circle. 1 MOA at 100 yards would equal ~1" line.
of course if you wanted to say it's a 1 MOA cone then it'd be a 1" diameter circle.

MEATSAW
December 12, 2009, 08:21 AM
The cone was what I was getting at. I was just curious if the 1" line was from center to edge, or edge to edge. Thanks for the tip.

Bud Helms
December 12, 2009, 08:31 AM
Minute of Arc (or Minute of Angle) is an angular measurement: 1/60th of a degree. It is not a line. It is not a circle. It is the subtended portion of a circle, regardless of diameter. As diameter increases, the subtended portion of the circle is a larger measurement, but the angle is the same: 1/60th of a degree.

We refer to the subtended portion of the circle as a line, but in truth, it is an arc. A one inch wide line on a flat target is an approximation of the arc on the circle defined by the angle. In two dimensions, that line is a chord which cuts the subtended arc end-to-end (along the perimeter of the circle).

So, it occurs to me that Ofir may be asking for the typical group sizes of the M16 vs M4. It looks like we got involved in the definition of MOA (arc and angle). That is partly because of the way the question is worded, BUT I still think we missed his question. I'll leave that to you M16/M4 shooters. I only have one MBR and that's a Steyr FAL. So, I have no comment on that.

Ofir
December 12, 2009, 09:26 AM
Lets just say i undersatnd what's MOA means :)
what's the M16 MOA if you know what i mean?
or the M4

Bud Helms
December 12, 2009, 09:29 AM
HA! I was right. :D

Ofir
December 12, 2009, 09:30 AM
:) yes you did

Ofir
December 12, 2009, 09:34 AM
i think the M16 is 1 MOA but i'm not sure...and about the M4 i have no idea
BTW with M193 ammunition

sneaky pete
December 12, 2009, 02:39 PM
old Sneaky Back: I remember way back our shooting coaches talking about the general accuracy of the M-1 Garand( my TO&E weapon at the time) and they seemed to feel that it was a 2>3 MOA gun using Gearic mil-spec 150 gr M-2Ball ammo(30-06). I purchased a '43 springfield Garand and Tweeked it up(a lot) and an able to get 1-1/4>1-1/2 inch 10 shot groups(supported) at 100 using Korean M-2 ball. I would expect that the m-16/m4 (mil-issued) using mil- spec 62gr ball ammo would be in the same 2>3 MOA range. Now needless to say that rifle can be Tweeked-up to obtain 1 MOA +/- however a lot depends on the tweeking AND the Ammo used. I've got a target AR-15 (scoped) that I have shot a 10 shot group of 0.378 inches at 100 yds(supported).I hope that this answer is more in line to what you were seeking?? THANX--SNEAKY:)

LukeA
December 12, 2009, 03:24 PM
I think I remember reading on here that M4s are accepted by the military with a 4MOA ten-shot group.

Quentin2
December 12, 2009, 04:58 PM
I think the question was too ambiguous to answer properly. MOA with carry handle sights, or an Aimpont, or a good scope, or mounted in a fixed rest? I think 4 MOA sounds about right for either the rifle or carbine but they can do better - depending...

jen45acp
December 12, 2009, 05:08 PM
If your rifle shoots at or better than 1 MOA with a certian brand of ammunition, then the largest grouping from center to center of the bullet holes on the target at 100 yards would be 2.100 inches. ;)

Jimro
December 12, 2009, 05:12 PM
With service ammunition you can expect 3 MOA from an M16 and 4 MOA from an M4 from sandbags. Like anything, some rifles will shoot tighter than that.

With match ammunition the numbers get smaller.

If you shoot MOA or better, a group center to center will be one inch or less at 100 yards.

Jimro

Double Naught Spy
December 13, 2009, 09:41 AM
If your rifle shoots at or better than 1 MOA with a certian brand of ammunition, then the largest grouping from center to center of the bullet holes on the target at 100 yards would be 2.100 inches.

Um, no.

December 13, 2009, 09:45 AM
service ammo M-16 type 1.5 to 2.5 inch...M-14 2.5 to 3.5.

MEATSAW
December 13, 2009, 09:56 AM
I have heard (may or may not be true) that M16s only need to shoot 8 MOA to pass military standards and then be issued. That sounds horrible and indeed it is, but a pop-up target at 300 yards would still be able to be hit (somewhat) consistently even with an 8 MOA rifle.

Like I said, I am not sure if that is the exact truth, but it sounds right to me. (considering the condition of some rifles in our military...)

When I bought my Bushmaster 20" HBAR as stock as could be I was shooting about 2-3 MOA or so with the iron sights. Since then I have modded it up quite a bit (still the same barrel and internals) and topped it with a Leupold Mark 4. Now I can average 1 MOA all day.

December 13, 2009, 10:03 AM
8 inch is a bit extreem but they used the same standards as the M-1 and M-14 as that was what had been in the books since like 1936. 6.5 inch comes to mind.

Candiru
December 13, 2009, 10:17 AM
Here's an article on the accuracy of various top-tier ARs. (http://230grain.com/showthread.php?t=66619) Might be somewhat relevant.

Art Eatman
December 13, 2009, 11:07 AM
As-issue, out-of-the-box military ARs of whatever sort oughta be able to hold maybe two or three MOA with iron sights. Some will be better.

Top of the line quasi-custom AR-15s will do a lot better, particularly with scope sights.

kraigwy
December 13, 2009, 11:29 AM
Can anyone tell me the MOA of Colt M16/M4 differences?

This question confused me, maybe its because I haven't had enough coffee yet but.

A MINUTE OF ANGLE IS A MINUTE OF ANGLE REGARDLESS OF WHAT GUN, or ammo, or even no gun and ammo.

But I'm still confused as to the orginal question.

Accuracy of a giving mass produced gun like STANDARD M16, 4, M1s, M14s etc. is a direct result of when they came off the assembly line.

New equipment, machinery or what ever is gonna produce tight tollerances where as the machinery wears out, the tollerances loosen up. Standards are set, when the tollerances exceed those standards, the machinery is replaced or repaired.

Some people, like White Oak (just an example) make target versons. Their tollerance guide lines are more strict, they are selling to target shooters where as the military had to feed hundreds of thousands of soldiers, who for the the most part can't shoot well enough to tell the differance.

Then the army desides they need more accurate guns for the service teams of the DMP (Desinated Marksman) so then send the guns to the AMU or simular places to have them Matched Out.

We as shooters deside what we are gonna do with the gun and buy accordingly. If you want to shoot beer cans at 100 yards, then pretty much any off the shelf AR will work, it you want to shoot 1000 yard service rifles then he's gonna have to pay big bucks for a WOA or simular rifle.

What MOA has to do with it? Well its too early, but I'd say NOTHING.

MOA is MOA

MEATSAW
December 13, 2009, 11:57 AM
Accuracy of a giving mass produced gun like STANDARD M16, 4, M1s, M14s etc. is a direct result of when they came off the assembly line.

In this case also a direct result of who had it before you and how it was used/abused.

I think there is a bit of a difference when you are talking about buying your own AR, and getting one issued to you in the military. In the case of buying your own I would expect that new ARs should be able to get to 1.5 MOA at the least once you find the right load.

If you are asking about an M16 or M4 that you will be issued from the military... as long as you can knock down the evil green men (pop-ups) well I wouldn't worry too much about the MOA.

kraigwy
December 13, 2009, 12:06 PM
OK after a couple more cups of coffee, and re-reading the post, I am starting to see more clearly.

We're not talking MOA per se, we are talking group size.

Palmetto-Pride
December 13, 2009, 12:22 PM

Did anyone else find this test to be flawed? For some they did 4 shots vs 5 shots and then it goes on to say the shots were not all taken on the same day and or weather conditions and in the beginning it says the same lower with a Magpul PRS stock was going to be used on all the uppers, but then it kind of sounds like they didn't because it says how not all the stocks were sitting in the rest the same.........this article left me......:confused::confused::confused:

MEATSAW
December 13, 2009, 12:34 PM

Did anyone else find this test to be flawed?

I thought the same. I would not use what you see here to compare the different rifles "tested." I think it is a good indication of what you can do with a particular model if you happen to own one of them. Drawing any other conclusions is risky at best.

bcarver
December 13, 2009, 12:40 PM
I think he was asking what one click of his sight is in moa.
I think a1 sights are 1 moa to 1 click. a2 sights are 1/2 moa per click.(some being 1/4)

Relentless Pursuit
December 13, 2009, 12:51 PM
In broad brush strokes a minute is an inch at 100yds and is lineal.
That allows for rapid extrapolations of agg sizing or holdoffs/comeups.

At 100yds is there a difference in the accuracy potential of a 16" AR as opposed to a 20"? Nope. As range increases the longer tube's added velocity will slip conditions better and the increased sight radius is a boon for driving irons,but in a best case scenario for each(quality fodder,good glass,sound operator,good conditions and a floating HG)...they are literal birds of a fether.

Barrel length equating to "more accuracy" is an aged Wives Tale and often time less is more,if only because increased rigidity will often bear much in the way of fruit.................

44 AMP
December 13, 2009, 02:29 PM
I have heard (may or may not be true) that M16s only need to shoot 8 MOA to pass military standards and then be issued

Back in the 1970s the standard for the M16A1 was 8 MOA for overseas ship-ment. Rifles that wouldn't do that well, were retained in the States, for training use. I'm not sure when this standard was actually tested, perhaps when they came off the assembly line , as I can guarantee you that no M16 in the hands of line unit ever got tested for accuracy. Functionality was the sole standard. As long as the rifle functioned, and met the appearance standards (less than 3 broken tabs of the handguard, for instance) it was good for service use. As a Small Arms Repairman in those days, I handled, inspected and repaired several thousand M16A1s, and at less than depot level maintenance, firing tests were never conducted even for functioning, let alone accuracy. All testing was done with guages, by eye, and if you were fortunate, dummy ammo.

Now, thats just the GI standard for the rifle. The ammo standards of the time were 2" group at 200 yards for M195 ball ammo, and 5" group at 200, for tracers.

Today's M16 and M4 should shoot better than 8 MOA, the civilian ARs generally do.

Ofir
December 13, 2009, 02:46 PM