What are the differences between the M16 and M4

Discussion in 'Rifle Country' started by grter, Oct 30, 2014.

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  1. grter

    grter Member

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    I am partial to the M16 and M4s do not seem to impress me although there are some noteworthy improvements.

    What are these improvements and are they really a big deal ?

    Some of this is rheterical in my part but I would still like to generate a much needed educated comparison and would find the different opinions interesting
    .
     
  2. HKGuns

    HKGuns Member

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    4 inches.
     
  3. Sam1911

    Sam1911 Moderator Emeritus

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    First off, there's a lot more to the variants in the hands of our servicemen than just "M16" and "M4." All the "A2" and "E" and "X" and whatever other versions all have different combinations of features, so it gets a little confusing. Barrel length, receiver style, upper style, stock type and length, fire control group, etc. all are now optional features of the different models.

    However, in general, the M4 types feature a collapsible butt stock which helps smaller shooters as well as lets soldiers handle their weapons more comfortably when wearing body armor and other gear. They also have shorter barrels, good for maneuvering in small areas and all sorts of vehicles (which most of our troops spend a LOT of time in and out of these days). The M4s feature a faster twist rate than the OLD M16 barrels did, good for stabilizing a wider variety of bullet types. There are semi-, full, and burst options. The newer versions allow for easy mounting of optics, which are pretty universal these days in the services.
     
  4. MachIVshooter

    MachIVshooter Member

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    Without getting into tremendous detail:

    M16 & M16A1: carry handle, 20" pencil barrel, full auto, triangle handguards, fixed stock

    M16A2: carry handle, 20" government profile barrel, 3 round burst, round handguards, fixed stock

    M4: carry handle or flat top, 14.5" government profile barrel w/M203 cut, round 7" hand guards, 3 round burst, adjustable stock

    M4A1: 14.5" flat top, government profile barrel, w/M203 cut, round 7" hand guards, full auto, adjustable stock

    Civilian title I M4gery: same as M4/M4A1, but 16" barrel (or shorter with permanently attached flash hider to make 16"), and obviously semi auto only.
     
  5. crazysccrmd

    crazysccrmd Member

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    The M4 is a huge improvement over the M16. It is lighter and easier to use when loaded up with gear. The difference shooting both is pretty much nil when in normal clothing, but once you put full kit on the M16 is just awkward to handle.
     
  6. d2wing

    d2wing Member

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    The M-16 with it's 20 inch barrel launches bullet at optimum speed gaining the shooter more range and lethality. Also the rifle action is smoother and mechanically more reliable as recoil pressure lower and comes later allowing better extraction. The M-16 is a rifle, the M-4 is a carbine. The rifle is generally better for long range, the carbine is better in close quarters. I used a real M-16 in combat. After starting with a M-14 the M-16 felt pretty small and handy.
    My first civilian AR was an M-4 style. I did have extraction problems with it, solved by new extractor polished chamber and H2 buffer. I recently built a rifle and like them both. For me the rifle is more useful because I hunt with it and like the better accuracy and range. But there is little difference. The M-4 type is more handy and better in close quarters. I am happy with both and would be happy with either one in nearly any situation but I could understand a preference for the M-4 style for home defense or even combat.
     
  7. Onmilo

    Onmilo Member

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    The M4 has the nifty slidey tube buttstock...
     
  8. grter

    grter Member

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    I heard the old 55 grain bullet (M193) launched from that 20 inch 1 in 12 twist barrel (M16) was a lethal high speed screamer that inflicted wounds so devastating NATO considered it inhumane.

    The unusually long for it's weight 62 grainer (M855 also known as SS109) accepted by NATO has better penetration (one side of a steel helmet at 600 meters) and is considered more humane. This is the one currently used by the military in the 14.5 inch barrel (16 inches with 1.5 inch suppressor added) of the 1 in 7 twist M4. I wonder how that one would perform in a 20 inch barrel with a 1 in 7 twist rate.

    Also my understanding is all 3 round burst ARs have trigger pulls that are garbage. The trigger pull on the M16A1 is great as far as I am concerned. Do the semi/full auto versions (NON 3 round burst versions) of the M4 have good triggers ? That is one I really don't know the answer to.
     
    Last edited: Oct 30, 2014
  9. MachIVshooter

    MachIVshooter Member

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    The FCG for full auto is not much different than semi-auto; the rear of the trigger is open & a tad shorter, the disconnector has a tail, the hammer has another hook, and there is a third pin for the auto sear. But the A1 FCG uses the same springs and has the same primary sear engagement as the semi-auto AR FCG.

    IOW, the trigger pull on an M16A1 or M4A1 would be the same as your typical commercial AR.
     
  10. d2wing

    d2wing Member

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    That nifty slide buttstock is a 2 way street. I like it on my carbine, but I like the fixed stock on the rifle. From my training in the Army, old school, I like the rifle way better for hand to hand combat. You can smash a guys teeth in or bash his skull in much better with a rifle butt. I hope I never have to do that but I do know how.
     
  11. grter

    grter Member

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    Provided I am not in a cramped up confined space judging from the looks of the newer M4s I think I would choose the ergonomics of the older M16 over the M4.

    In my opinion and based on my experience handling it the M16A1 with a light weight pencil barrel is a dream come true when it comes to ergonomics and is the swiftest pointing, most natural feeling rifle I have ever handled.

    I can only imagine the heavier barrel of the M16A2 would probably throw of the balance although I have never handled one.

    Does the shorter barrel of the M4 remedy this ?
    Is it even a consideration ?

    Are the heavier barrels even needed. I do know the 1 in 7 twist is needed for those unusually long for their weight 62 grain bullets and the 1 in 12 twist barrels failed accuracy tests in Alaska during the waning times of the "commie scare" due to Friction from the colder denser air.

    62 grains is really teetering on the end of the max weight a 1 in 12 twist was designed to stabilize anyway. They tried 1 in 9 (the compromise twist that should be able to stabilize both the 55 and 62 grain bullets but they finally settled on 1 in 7 which is not really optimized for 55 grain bullets.

    They taught us to just put the tip of your finger on the trigger and squeeze until it breaks. I got pretty good at pointing and hitting stuff far off quickly with that beat up M16A1.

    I don't think I would have done as well with those 3 round burst triggers that are said to not only be bad but have a different weight after every squeeze. Do those triggers feel more like double action triggers as opposed to the distinctive single action trigger breaks of the non 3 round burst versions.
     
    Last edited: Oct 31, 2014
  12. crazysccrmd

    crazysccrmd Member

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    The three round burst trigger feels just like a commercial AR trigger. Relatively stiff, gritty, a good amount of creep, but a fairly consistent and positive breaking point. I've never had issues shooting an M4 accurately with irons, M68s or ACOGs. You can play the dime drill game all day and not drop it if you know what you're doing.
     
  13. d2wing

    d2wing Member

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    In Vietnam I shot out of the window of moving vehicles and did not have any trouble. Also I was trained in quick kill technique, I don't think it would work as well with anything other than the original M-16.it was very quick to shoot for me. The newer versions seem bulky, heavy and don't point as nicely. I guess things are different now. Less about gun fighting skills and more about optics and gadgets.
     
  14. GRIZ22

    GRIZ22 Member

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    The triggers on full auto M4s are like a standard M16 trigger. Light years better than a 3 rd burst trigger.
     
  15. Onmilo

    Onmilo Member

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    3 round burst trigger mechanisms continue to index the burst ratchet in single shot mode.
    This means every trigger pull is different than the previous AND if you switch the selector to 3 round burst it will only fire the number of rounds left on the ratchet so your first three round burst can be one, two or three rounds as then will be your last.

    AFAIK most M4/M4A1 Carbines in use still employ the three shot burst mechanism.
    Only SOCOM issued M4A1 weapons have mainly been converted to full auto function selective fire mode.
     
  16. lemaymiami

    lemaymiami Member

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    Reading the various comments was interesting. I trained/qualified with the M16 all those years ago (after first training up with M14 that M16 was breeze to score well with...). My son, currently in the service was trained up with the M-4... Not surprisingly he thinks that it's the most outstanding weapon going. The two of us are separated by more than forty years between basic training cycles if that means anything...
     
  17. MistWolf

    MistWolf Member

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    The 55 grain bullet works fine in twists from 1:12 to 1:7. When fired from a 1:12 twist, they noted that sometimes the bullet sometimes destabilized in the human body, creating a more devastating wound channel. Problem was, the bullet could not be relied on to destabilize every time. Later, they tightened the twist to 1:7 and came up with a new, longer and heavier bullet designed to destabilize more consistently. NATO never said anything about it being "inhumane". The military never used a 1:9 or 1:8 twist. When the military went with the 1:7 twist, Colt offered rifles in the 1:9 twist on the civilian market

    It was the 1:14 twist they had problems with in arctic conditions.

    There are modern flat top 20 inch ARs with lighweight barrels that have good handling characteristics and allow the advantage of mounting modern optics. Pick a configuration you like and go shoot. I have ARs with 20, 16 and 10.5 inch barrels and I like them all
     
  18. moxie

    moxie Member

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