Thoughts on the M16A4


To preface this, let me state that I served in the Marine Corps as a rifleman and that I carried a FN M16A4 in Iraq.  The above picture is of the rifle I carried in Iraq.

I see online that some people have a hardcore love for the M16A4.  In reality, it is not that good.  Please don’t get me wrong it isn’t a bad rifle, but it is not a great one.

When considering the M16A4 uses as a combat rifle it is ok, but not as flexible as a M4.  If you employ the M16A4 as a battle rifle, like the M1Garand, M14, and M16A2 that preceded it, it is great.  However a battle rifle is not suited for all combat.  The longer length of the M16A2 & M16A4 along with the fixed stock, makes for a less then ideal rifle for close quarters battle or for use with body armor.  Its’ 40 inches of length makes the rifle more awkward when egressing vehicles.

The main benefits of the M16A4 over the M4 are higher muzzle velocity and longer sight radius.  The benefits of increased sight radius are negated if we use optics.  While more velocity is always nice, it is shot placement and bullet selection that is very important.  Outside the military, we are not limited to M855 ball ammunition, and there are plenty of alternative that will function excellently in shorter barrels.

For a civilian, I can see why someone would want to reproduce a military rifle.  However from a cost effectiveness standpoint, building a M16A4 clone is silly.  Few companies make M16A4 style uppers, and there is good reason for that; they just don’t sell well.  The Knights M5 RAS quad rail used on the rifle runs about $320 dollars new.  For far less then that you can get a lighter, cheaper, free float rail.  The Government profile of the M16A4 combined with a heavy non-freefloat rail does not make for the best accuracy or consistency.  A proper M16A4 clone is neither accuracy enough for precision competition, nor as handy as a M4 style carbine.

While I was in the Corps, there was a big mentality that the M4 was just such an inferior weapon system.  I believed this for a long time, till finally I started to realized that if the entire Army was fielding M4s, it can’t be junk.  However our Army does make mistakes, but other groups like the SEALs, some of the British, German, Irish, and Australian special forces, etc.  Many elite forces around the world choose the M4 or variants(like the C8SFW) for their mission over their own countries standard issue rifle, or full length M16s.  Clearly the M4 has the reliability and capability for those end users mission.

The M16A4 is a battle rifle, however the M4 carbine is a versatile jack of all trades that is better choice for most individuals.

Picture of my last M16A4 clone rifle before I finally decided to move away from the M16A4 platform completely.


  1. Real rifle infantry mqn use m16s tbose who cant shoot and know how to use bayonets and rifle combat skills use m4s. None of you know what the he’ll you’re talking about the m16a4 is far more reliable than any small associates m4. In Iraq and Afghanistan army guys were always complaining for good reason their m4s has white range and the afghans could reach them with ak47 rpd and sks. Even ranger units and the 10th mountain we’re wanting the m16a4 plus you cannot in any way use the m4 with a bayonet or use it for but strokes which is the core of self defense with a rifle. I spent seven years in the infantry and the m4 was damn useless in firefights they needed range. Why the he’ll do you think the army targets upper body targets at much shorter ranges than marine rifle targets which uses point range accuracy than some cheap excuse of army target practice. The m4 is for people who can’t shoot past 500 yds. I would stake my life on the a4 over any m4. Even the army gives out the a4 to designated marksman before the m14 was reissued. Short barrel rifle are garbage when it comes to firefights. An AK can shoot longer distance than an standard issued m4 the army uses. Sgt 1st bn 5th marines Charles company weapons plt 0351 2001 OIF 1 through 3

    • I take it you haven’t heard that the USMC switched to the M4?
      Us Jarheads aren’t all the brights bulbs in the bunch, many of us drank the “M16 is better than M4” koolaid. Just because the people kept saying it, doesn’t make it true. Throwing out a Marine rank with your gibberish just makes all of us look dumb.

    • I suggest you look up bullet flight paths for 5.45×39 out of a M4 vs 7.62×39 out of a 47.

      Then come back and say the AK out ranges the M4. Also the M16 gets maybe 200FPS extra velocity out of the extra 5.5″ of barrel.

    • I like you’re post Chris I thought I would ask since I’m pretty new to building firearms I have never done it before. I’m looking at building my own A4 starting with a stag arms model 4H upper for my A4 clone along with a stag A2 buttstock I’m looking at a free floating rail as well any suggestions that you have as far as buying parts and saving money.

  2. So it’s not that the M4 is the better rifle, generally. It’s that, given your circumstances and experiences, the M4 was the better option provided your operating environment, engagement ranges and choices in accessories. Should there have been a change in scenarios, you might agree the A4 could turn out as better than the M4.

    These are just tools. There’s rarely one tool that fits all situations. We use what’s best for the task at hand. What you were dealing with favored the M4. That’s what it seems like, from your opinion.

    • I get what your saying, but I don’t see many realistic combat events that favor the A4.
      The old general arguments for the A4 were better terminal effects, better accuracy, better reliability.
      The accuracy bit has been debunked.
      The M4 has shown it self to be more than reliable enough for combat. It is when undisciplined soldiers attempt to use it as a light machine gun that they have it fail.
      As for terminal effects, going to the 5.56 is a compromise to being with. But we have seen the 14.5 inch barreled M4 get the job done. Hell the USMC feels that a 16.5 inch barreled carbine is a good enough automatic rifle. Now we even see lots of shorter barreled guns fielded by various groups around the world. The X95, all the 10.4 HK416s, MK18s, The Canadian 10 inch carbines, The G36C, the short Polish 5.56 AKs, the Sig 552 commando, etc. Tons of fighting firearms with very short barrels. Super short 5.56 guns are not optimum, but they work.
      But how is the A4 inferior?
      The A4 uses the KAC M5 rail. While excellent for its time, now it is very heavy, costly, and does not free float the barrel.
      The Government profile is just silly, just like most things the government designs.
      The long fixed stock was made for prone competition shooting and does not fit many of our service members, and that is before they have to wear body armor.

      Don’t get me wrong, I have a soft spot in my heart for the A4. But at this point it is primarily a rifle like the Mosin and the M14, where its overweight fans preach online about how it is the finest fighting firearm of all time.


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