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3 round burst vs Full Auto

9K views 44 replies 26 participants last post by  SC Tiger 
#1 ·
I have another question on full auto.....

As I recall, a few years ago the Army went from full auto to 3-round-burst for the M16/M4. The reasoning was that 3 round burst was easier to control and wasted less ammo.

Now, my understanding is that they have gone back to full auto. Is there a reason for this? Having never fired either I cannot say for sure but it would seem that a 3-round burst used continually could make for a reasonable approximation of full auto without the wasted ammo.

For those wondering - the Las Vegas thing has put full auto in my mind a little bit. But I am FAR from an anti-gunner (I've been a member here for years but rarely post in this forum). I'm really just curious about this.
 
#2 ·
The Army went to 3-rounds bursts more than "a few years ago". They decided on that feature when the M16A2 was developed and introduced back in the early 1980s. So it's more like a few decades than a few years.

The 3-rds burst feature was crap not because of the philosophy but because of the weird ratchet system Colt concocted that didn't reset itself after the trigger is release. If you don't hold the trigger down long enough for a full three rounds, the next time you pull the trigger, the remainder of the burst fired. That means if you shot one round and released the trigger then the next time two rounds would come out before the system resets itself.

My guess as to why the Army decided to go back to full-auto was probably due to all the close combat/house clearing fighting. That's only a guess.

Frankly, the burst or full-auto feature is unused 99% of the time. Soldiers of my generation were well discouraged to use it on rifles.
 
#8 ·
The Army went to 3-rounds bursts more than "a few years ago". They decided on that feature when the M16A2 was developed and introduced back in the early 1980s. So it's more like a few decades than a few years.

The 3-rds burst feature was crap not because of the philosophy but because of the weird ratchet system Colt concocted that didn't reset itself after the trigger is release. If you don't hold the trigger down long enough for a full three rounds, the next time you pull the trigger, the remainder of the burst fired. That means if you shot one round and released the trigger then the next time two rounds would come out before the system resets itself.

My guess as to why the Army decided to go back to full-auto was probably due to all the close combat/house clearing fighting. That's only a guess.

Frankly, the burst or full-auto feature is unused 99% of the time. Soldiers of my generation were well discouraged to use it on rifles.
Hey - I'm old, alright! The 1980s is "a few years ago" to me! :rofl:

Seriously I couldn't remember when it was and honestly didn't know the exact time. I know it was being discussed but never figured out how the hell they did it.

Did it have the reset problem if you went back to SA after the burst? In other words, you go to burst. Fire one round. Then go to SA. Does it fire 1 round on the next pull or two? Based on your description I can surely see why the Army went back to FA.

As far as how often it is used - my father's experience is similar to yours. Very much discouraged. Especially since an M-16 will empty a 30-round mag in under 3 seconds.
 
#3 ·
I was unaware that they had went back to full auto. I was in when they went to 3 round burst and I thought it made a lot of sense. If you don't hit on the first round you are not going to hit on the 5th, certainly not on the 10th and the twentieth is not going to be in the neighborhood. Now a full auto true machine gun is a different story, its heavy, its on a bipod or a tripod that makes it more stable so a beaten zone is created instead of a line going up and off to one side.

But, yes, the way it was implemented was not good. If you only fired two shots, the next burst was going to be one shot and your first reaction was going to be, malfunction.
 
#5 ·
It depends on infantry tactics. The more they change, the more they become alike.

During Vietnam, the point soldier of a patrol, if he saw an ambush or an enemy soldier, would fire a full magazine down the trail. The intent was to put a lot of metal downrange and kill and maybe break up an ambush. Soldiers behind him would then open up. This was told to me by a 1st Infantry Div. soldier and a Marine infantryman. (They both loved the M16 compared to the M14.)

During WWII, Marine after action reports recommended that many full auto weapons (Tommy guns or BARs) be placed in the front of patrols for the reasons noted above. The Marine Raiders adopted 4 man fire teams centered around a full auto weapon.

In World War I, soldiers equipped with shotguns loaded with buckshot (known as trench sweepers or trench brooms) would again, put a lot of metal downrange in a short period of time. A BAR was used for the same purpose.

No one stood around in a classic offhand rifle shooting position firing aimed shots at an enemy at very close range.
 
#6 ·
Full auto for novelty and burning large amounts of cash, 3 rd burst if your operator as **** at the range- if they even allow it these days , and semi auto for 99.99% of realistic civilian shooters.

Select fire is definitely “cool” and collectible and I’d own one if I could afford it but novelty for civilian use. You will not be doing mag dumps in any real world situation, SHTF scenario going through your mind unless you are Rambo.
 
#7 ·
You can dump a lot of hot lead downrange while on semiauto as well. You don't need full auto to discourage the enemies or to overwhelm their ambushes.

Advantage: you don't run out of ammo as fast as shooting rapid fire semiauto. You can at least have some semblance of aimed suppressed fire that way too. I know that there are a lot of documentary videos showing the Navy SEALs blazing away on full autos, but they're the SEALs and not Joe Blow.
 
#11 ·
When deployed with the M4A1 (semi/full) I might have went FA a small handful of times. Only real use for it is for suppressing fire, say down an alleyway that others are trying to cross. The other 99% of the time was spent in semi.

There are uses for it, especially the "operators" that get their hands on some very controllable SMGs (think MP5/SD models) but the vast majority of the military doesn't have a huge need for it, especially with the LMGs close by.

The M4 I went to basic with was Semi/Burst and we only flipped to burst once or twice just to get us accustomed to how it felt.
 
#13 ·
I can't speak in regards to Military applications, but I have done quite bit of full auto target shooting with M16's. Over 70,000 rounds worth.

When firing a burst into a distant target (25-100 yards), the first two shots usually land on the target, then shots 3-6 tend to miss, and then shot 7 through the end of the magazine all go back into the target. With that in mind, you should either fire two rounds or dump a whole pile. Shooting a 3, 4, or 5 round burst is a bad idea accuracy wise.

Tony
 
#15 ·
Full auto in combat is for two reasons, an area target or suppressive fire. It has been proven time and time again that 3-5 round bursts are most effective at this while still considering ammo conservation in a combat scenario. I've seen guys at the range get chewed out for doing what you prescribe.
Only time you go cyclic and open the ***** up is when you need to put down a whole hell of a lot of fire to keep their heads down.

Think fire superiority. That's it. That's what you need automatic rifle fire for.
 
#16 ·
I have no idea. I never used the M16A2 like that so, I don't know. I used the 3-rds bursts at the range a few times just to say I did it but that's about it. Never used it in combat or training and never flipped the safety lever back and forth between the modes to see what's going on either.


I can't remember if the Army or Marines went back to full auto first. I can't remember if the M16A4 came out before the M4A1. The jarheads went to the M16A4 and it had full auto. The Army's M4A1 had full auto.

I also can't remember if it was the Army or Marine Corps wanted the 3-rds burst for the M16A2 either. I remembered the Gyrines wanted that fancy rear sight for "precision long range shooting".
I can't remember either. Just shows how rarely it gets used.
 
#17 ·
Yeah, the burst rifles were interesting, and as a Colt-trained LE armorer they added a little extra complexity because of the burst cam & spring.

In my first armorer class they had a burst gun as one of the rifles for students to use, and it wasn't popular among the armorers. For the final sign-off, when students had to assemble a stripped rifle and have it pass inspection by the instructor in order to pass the class, I decided to choose the burst gun for my sign off. I figured if I could pass the class using it, I'd been paying enough attention.

One thing the Colt guy mentioned about the burst cam was that "it was always counting, but never knew where it was". The only way to know your first trigger press was going to be a 3rd burst was to shotgun the upper/lower and manipulate the mechanism to set it that way, which seemed a little complicated.

It was occasionally fun to run our sole burst rifle for range use, but only our special enforcement teams ran select-fire or burst guns. Regular Patrol rifles were always SA guns (which I fully supported).
 
#18 · (Edited)
IMHO...

Three round burst came about because...

It was easier to design a piece of machinery, than it was to teach the soldiers to release the trigger in times of stress.

Further consider, the "burst trigger" came about in the early 80's.

The U.S. was only recently out of Vietnam at the time.

In typical military fashion, we continue to design equipment to fight the "last war", not the next one.

For the jungles of Vietnam, the burst feature might have actually worked.

In the clearing of Afghan villages.... (short, quick, and dirty actions) the full auto is what you want.

Consider, we come out of WWII where the U.S. was armed largely with .30-06 caliber weapons.

In the immediate post war period, the U.S. fields the M-14 .7.62mm rilfes (.308).Along with M-60 M.G.'s.

We quickly wind up in Vietnam where the full power rifle is not viewed as an advantage.

Soooo, the military adopts the 5.56mm cal. weapons.

Certainly a good fix for the situation.

Soooo, now what happens.... The military finds itself in a desert war where the longer ranges would allow for the .30 cals. to shine.

Now there s a move to bring the M-14 rifle and similar back onto the line.

Now, I certainly take no joy in this, however consider.

What is the appropriate weapon should we find ourselves engaged in a "winter conflict" in an unnamed Northern Asian nation?

In my mind, this sort of scenario would call for a longer ranged better penetrating weapon system.

BUT.... What the heck do I know.

BTW, before closing... I really do like 5.56mm weapons for most uses.

And see them as a viable compromise.
 
#19 ·
It depends on infantry tactics. The more they change, the more they become alike.

During Vietnam, the point soldier of a patrol, if he saw an ambush or an enemy soldier, would fire a full magazine down the trail. The intent was to put a lot of metal downrange and kill and maybe break up an ambush. Soldiers behind him would then open up. This was told to me by a 1st Infantry Div. soldier and a Marine infantryman. (They both loved the M16 compared to the M14.)

During WWII, Marine after action reports recommended that many full auto weapons (Tommy guns or BARs) be placed in the front of patrols for the reasons noted above. The Marine Raiders adopted 4 man fire teams centered around a full auto weapon.

In World War I, soldiers equipped with shotguns loaded with buckshot (known as trench sweepers or trench brooms) would again, put a lot of metal downrange in a short period of time. A BAR was used for the same purpose.

No one stood around in a classic offhand rifle shooting position firing aimed shots at an enemy at very close range.
My father was a platoon leader in Vietnam. Infantry.

He discouraged use of full auto, but that was "in general" and I never asked if he let them use it in any situations, etc. I do know he was not a fan of it's use in general.

He did have the same opinion of the M16 vs M14 though. He did not like the M14. He said it was too heavy for an infantry weapon (based on his experience in Vietnam of course) and that if it got any dirt on the bolt's cam roller, it would jam.

I have read that basically an infantry squad was built around the FA weapon (M60 at the time) and the riflemen were to protect it. I don't think that is 100% correct though.
 
#20 ·
was built around the FA weapon (M60 at the time) and the riflemen were to protect it. I don't think that is 100% correct though.
Maybe that was the infantry doctrine in Vietnam but it sure wasn't in my times (1980s). The machine guns (medium or light) support the infantryman's movements.

They suppress the enemies while the infantry maneuvers in close for the kill.
 
#28 ·
The rifle(s) I used from `88 to `98 were the burst variety. My brother has a Vietnam-era full auto M16 that is fun to shoot, but those mags empty quick!

So, I've actually shot both varieties and preferred the increased control of the full auto version.

My brother's...

Firearm Gun Trigger Gun accessory Airsoft
 
#29 ·
Did it have the reset problem if you went back to SA after the burst? In other words, you go to burst. Fire one round. Then go to SA. Does it fire 1 round on the next pull or two? .
You would have to fire at least one round in semi auto mode to reset the cam from where it was stopped in the three shot burst position.
 
#36 ·
My memory is far from good anymore but what is coming back to me was if you cycled the bolt it advanced the count. At least that is what I remember from the function check.
 
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#30 ·
When I go to Front Sight in Nevada every year, the first day's lunch hour is spent shooting full-auto machine guns (if you desire). I never eat lunch on the first day. Lol. So, you get to shoot the following weapons:
MP5
Uzi
Mini-Uzi
M16
Thompson Sub-Machine gun.

The first time I was going to shoot, I asked the instructor if it was possible to keep the shots on target during full-auto. He said that it definitely was, except for the Thompson. That one seems hardest for most people. To prove it, he picked up the M16, leaned forward and emptied the magazine. All rounds were in the chest zone of the target from 10 yards. He then handed the rifle to me and adjusted my body so I was leaning pretty far forward. By the time I got to the third magazine, I was placing all rounds on target. The same with all other guns except the Tommy Gun. Even though it fires at a much slower rate than the others. My point is, I think anyone with any training can shoot a full-auto accurately.
 
#31 ·
I fired a M-14A1 in a full automatic rifle course, it had no burst control device. The shooter was taught to control the fire with his trigger finger. With a M-60 it was "Fire-A-Burst-of-Six", M-14 was "Fire-A-Burst-of-Three". All automatic fire was controlled by the shooter, machine gun or automatic rifle. When we changed to M-16s, everyone had a automatic rifle, but no one was taught automatic fire discipline. On the Job Training did not suffice. The Army did not want to take the time to properly train all Infantrymen so the M-16A2 had mechanical burst control that still needed training that the Army still did not do. Now it seems that training has improved.
Full auto fire can be used in many applications, but in my time mostly 'fire and maneuver' or 'perimeter defense' topped the day.

Aimed fire is way better than Automatic in most cases.

A Thompson with close to factory specs, AND a clean chamber, can be reasonably accurate. Front Sight's Thompson is well used and.... dirty! I have tried to shoot it without malfunction. I had better luck with their Uzi's.
 
#32 ·
How many people here have actually shot both a 3 shot burst and a full auto trigger, as in M4 and M4A1 trigger, because something major got missed here.

The three shot burst trigger sucks. I mean it sticks on ice. It’s gritty. And squishy. It breaks inconsistently. Its actual pull weight is higher than advertised and varies dramatically from rifle to rifle. And this is in semi. It’s just all around awful.

The M4A1 trigger on the other hand is worlds better. Don’t get me wrong, it’s still a milspec trigger, but it’s way better.
This is excerpted from the Wikipedia page for the mk12 rifle here https://en.m.wikipedia.org/wiki/Mk_12_Special_Purpose_Rifle
“Crane assembled all of its prototypes using either M16A1 or M4A1 lower receivers, because the full auto trigger group in these lower receivers provided a consistent pull while the more common 3-round burst trigger groups didn't.”

The special operations community quickly figured this out and went back to auto in all their triggers. The rest of the military is catching up still.

Best.
 
#37 ·
How many people here have actually shot both a 3 shot burst and a full auto trigger, as in M4 and M4A1 trigger, because something major got missed here.

The three shot burst trigger sucks. I mean it sticks on ice. It’s gritty. And squishy. It breaks inconsistently. Its actual pull weight is higher than advertised and varies dramatically from rifle to rifle. And this is in semi. It’s just all around awful.

The M4A1 trigger on the other hand is worlds better. Don’t get me wrong, it’s still a milspec trigger, but it’s way better.
This is excerpted from the Wikipedia page for the mk12 rifle here https://en.m.wikipedia.org/wiki/Mk_12_Special_Purpose_Rifle
“Crane assembled all of its prototypes using either M16A1 or M4A1 lower receivers, because the full auto trigger group in these lower receivers provided a consistent pull while the more common 3-round burst trigger groups didn't.”

The special operations community quickly figured this out and went back to auto in all their triggers. The rest of the military is catching up still.

Best.
Its not as simple as that. The military was trained to fight in open field battle. Where 3 round burst makes some sense. We got really good at it as the First Gulf War proved. That was quite probably the best open field battle trained Army the US ever had. Some one is probably about to say WWII, no if you look at the initial battles of WWII things did not go so well. The idea was to hit someone several times instead of once. Along comes 9/11 and now its fighting close quarters combat. Makes sense to have a room sweeper under those circumstances. Its going to take awhile to get good at open field battle again. For nearly a generation its been all CQB.
 
#34 ·
I spent a lot of time with an KH MP5/SD. About 10 years worth. I am also an NRA Subgun instructor.

Ours were full auto. After a little practice, I could easily fire 3 shots on full auto. Even 2 if I wanted too.

That was a very heavy gun. Supremely controllable, accurate and reliable.

I don't recall ever switching to full auto on a real deal. For two or three shots, I could just use the single shot trigger.

It was just "there" if needed I suppose.

I've got a Gold Trigger on my AR now. I can easily duplicate 2-3 burts at auto rate...and hit things.
 
#38 ·
How many people here have actually shot both a 3 shot burst and a full auto trigger, as in M4 and M4A1 trigger, because something major got missed here.

The three shot burst trigger sucks. I mean it sticks on ice. It’s gritty. And squishy. It breaks inconsistently. Its actual pull weight is higher than advertised and varies dramatically from rifle to rifle. And this is in semi. It’s just all around awful.

The M4A1 trigger on the other hand is worlds better. Don’t get me wrong, it’s still a milspec trigger, but it’s way better.
This is excerpted from the Wikipedia page for the mk12 rifle here https://en.m.wikipedia.org/wiki/Mk_12_Special_Purpose_Rifle
“Crane assembled all of its prototypes using either M16A1 or M4A1 lower receivers, because the full auto trigger group in these lower receivers provided a consistent pull while the more common 3-round burst trigger groups didn't.”

The special operations community quickly figured this out and went back to auto in all their triggers. The rest of the military is catching up still.

Best.
I saw it from the other direction, switching to the A2 from the A1. I really don't remember that much change in the trigger. So it might just be a better trigger being developed and installed 20 years later rather than the mechanism.

There was a big emphasis about not short stroking the trigger because of the counter when they came out. The idea was not to simulate a full auto by pulling it repeatedly. If that was the point there was no reason to get rid of the full auto function. The idea was to aim pull the trigger back, hold and release on a single target to achieve multiple hits on a single target. Attempting to replicate full auto would generally result in the counter screwing that up.
 
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