Army Converting M4 Carbines to M4A1 reports on the $120 million M4 to M4A1 conversion program

WASHINGTON (Army News Service, May 22, 2014) — A thicker barrel will absorb more heat in the new M4-A1 carbine, should a Soldier need to flip the selector to auto, according to Soldiers overseeing the new configuration now being added to the M4.

While shooting in the automatic mode is less efficient and not as accurate as firing in bursts, it has its place on the battlefield, explained Command Sgt. Maj. Doug Maddi, Program Executive Office Soldier, Fort Belvoir, Va.

“Soldiers need automatic capability while providing suppression fires during fire and movement,” he said, noting that Soldiers deployed to Afghanistan asked for that and are now getting it, an option absent in the M4, which only fired in semi-automatic and bursts. A new drop-in trigger allows the A1 to function with the automatic setting.

Maddi and others spoke May 21, during a media roundtable, marking the milestone of the first Army unit to receive the beefed-up carbines, 1st Infantry Division, out of Fort Riley, Kan.

The beefier weapon is not unknown to the Army. Soldiers in U.S. Special Operations Command have been using M4-A1s since 1994.

The tradeoff in weight and performance is something Soldiers gladly accept, Maddi said, noting that the M4-A1 weighs 7.74 pounds, compared to the M-4’s 7.46. The weight comparisons include the back-up iron sight, forward pistol grip, empty magazine and sling.

Another feature that’s new on the A1 is an ambidextrous selector lever, something that’s especially attractive to Maddi, who said he’s a lefty who often gets left out when it comes to equipment design.

Total program cost, including all the labor and hardware, is an estimated $120 million, he said.

Right now, conversions at Fort Riley are starting to get ramped up, with about 300 conversions being done a day, Maddi said. That works out to an entire brigade combat team getting A1s every week or so. And, those who are getting them are offering “resounding accolades.”

Thanks to Lance for the tip.

Steve Johnson

Founder and Dictator-In-Chief of TFB. A passionate gun owner, a shooting enthusiast and totally tacti-uncool. Favorite first date location: any gun range. Steve can be contacted here.


  • allannon

    While I’m not sure about the pricetag–I’m not sure how many M4s are out there–the barrel and selector make sense to me.

    I can see how while FA might be somewhat unusual, when you need it you _really_ need it. And if you add the fun setting back in, you need some way to help mitigate the heat.

    I do suspect, though, that the army is overpaying. I always assume that about the government, however.

    • Joshua

      500,000 M4’s will be converted…..or somethig around that number.

      The main benefit to the auto triggervs the burst o ne is trigger pull. The auto trigger group has one precise trigger pull, where as the burst has a different trigger pull for each tooth on the cog.

      • totenglocke

        $120 million total for 500,000 rifles comes out to $240 each. While it’s not obscene, it’s probably at least twice what it would cost a private company to do the same job.

        • clinton notestine

          Halliburtons never less than triple

        • Steve Truffer

          milspec s/sa/fa trigger groups are ~ $50 IIRC, and a heavy contour, chromed & threaded barrel can easily cost $190. Seem perfectly reasonable.

          • totenglocke

            You’re confusing cost to ordinary consumers versus bulk costs on a negotiated contract.

          • Steve Truffer

            Looks like the .mil gets m4’s for ~30% off. I’m seeing the barrel style I mentioned for $250. M16 LPK for $90. $340 total. 70% of $340 = $238. Looks inline with other small arms rates for the army.

          • HSR47

            “M16 LPK for $90”

            That sounds like the price for a complete LPK… They’re only universally replacing a total of 6-8 parts (trigger, hammer, disconnector, a dedicated spring for each part, and possibly the trigger/hammer pins). Given that a tuned “mil-spec” semi-auto trigger from ALG Defense generally goes for $45-60, I can’t imagine that a comparable number of parts costs even that much (ALG triggers involve more skilled labor, and are lower-volume parts).

            The barrels also are likely cheaper to an extent, largely due to volume: They’re buying 500,000 barrels and having them all shipped to the same place. As such, there are economies of scale involved that you and I can’t hope to touch.

            You’re also not figuring in the cost of shipping and installation (if the picture in the article is relevant, it implies that civilian contractors are doing the work).

          • Steve Truffer

            Ok, AK guy here, so my knowledge of AR/M16’s is limited. Doing the math, 70% (roughly the rate that the US military pays per M4) of $250 + $50 = $210, so $30 * 0.5mil = $15,000,000 to cover shipping and civilian labor.

          • Geodkyt

            “Total program cost, including all the labor and hardware, is an estimated $120 million…”
            So, it’s $240 per carbine, INSTALLED. Pefectly in line, cost wise.

          • HSR47

            You’re assuming that the government pays less than retail for everything they buy.

            Many government contracts stipulate how much time the government has to pay out, and the longer that period is, the higher the prices will be. Often, this results in them paying far more than they strictly need to, purely because the bureaucratic elements responsible for paying contractors move so slowly.

        • Geodkyt

          Since the price inlcudes the parts, fixtures* (unscrewing a barrel isn;t something you do while balancing it in your lap), tools*, and labor, $240 is actually a pretty fair price.

          * Yes, they are tooling up to do the conversions – it would take too long to have already established facilities do the conversions in addition to their regular work.

  • Dave Parks

    Now, where can I go to bid on those surplus M4 barrels?

  • Chris

    This is something they should have done like ten years ago.

    • HSR47

      Yes and no.

      They seem to have been holding out hope that they could get something better than the current Stoner-pattern rifles: Why spend money on what you have if you’re just going to replace it anyway?

      There has been one program after another to try to find something better, and the decision to convert the current stock of M4 rifles to M4A1 rifles only was only officially made once the most recent competition was finally canceled.

      In reality, it all boils down to politics: On the one hand, politicans like to take credit for getting the military shiny new equipment, and on the other hand there is a lot of doctrinal prejudice among the general staff of the armed forces (read: they don’t like new things: just look at what happened when we moved away from the M1, and again with the M14).

      If they had been able to get something better for a reasonable per-unit price, that obviously would have been the best option; Until there was final action on the various carbine competitions, spending lots of money on current stockpiles of carbines was contraindicated.

  • Gary from Michigan

    The M16/M4 platform has been in place a long long time and has proven itself in many wars. Replacing it doesn’t make any sense when it continues to serve its purpose. Yes, people complain about it every once in awhile as they do the 5.56 cartridge. The fact is, there isn’t anything better (or at least significantly better) in that caliber than that platform. It just works. Tweaking it once in awhile is a understandable and viable alternative to scraping it.

    • guest

      HK-416 is better by a wide margin, and that’s just a modestly deep modification of an M4, not even taking into account XM-9 and the plethora of other vastly more reliable and better built rifles.

      • Steve Truffer

        The US .mil is getting M4/M16’s for ~$750/ea. How much do these alternatives cost?

      • dp

        Better? Maybe, but quite a bit heavier and pricier.

      • Uniform223

        The HK416 aka M27 IAR in reality is marginally better. The only real benefit of it ( from what I know ) is that it runs better for SBR configurations and is more suppressor friendly, which is a plus for a lot of SOF end users. Though you don’t have to clean the bolt, you still have to clean and maintain the gas block and piston head. Also I learned from experience, If your one of those people who like to use that extended forward grip or the “Costa” C clamp grip, be careful of that gas block upfront.

        • HKGuns

          I don’t know where you’re holding or how much you are shooting, but neither of my HK AR based piston rifles exhibit any heat build-up around the hand guards. Zilch, Nada, Zero.

          • HSR47

            Full auto tends to heat guns up far more effectively than semi auto. Have you considered the possibility that he is relating his experience with the former rather than the latter?

      • John

        The piston recoil just sucks. It’s basically a jackhammer. I’ve shot the HK416 on full auto and it’s a handful. I also own the MR556. I can understand the army thinking it’s not worth the cost. DI is a lot smoother, especially on full auto.

        • CA

          The Germans aren’t as smart as they think they are. They always build things too big.

      • CA

        How is a weapon that works really well (the HK-416) better BY A WIDE MARGINE than another weapon that works really well, the M16/m4?. You read too much hype man.

      • HSR47

        Also, you seem to ignore the tendancy of the HK XM8 to melt/soften when it was actually used….

  • dp

    Does it mean that thru this conversion the 3rd burst is out? That may need a mod to lower in addition to removing ratchet, if it is correct.

    • Steve Truffer

      I believe they swap the whole trigger group, so the only potential discrepancy might be the selector says “burst” instead of “full” or “auto”. Just an AK guy’s thoughts after poking in ArfCom, though.

      • dp

        That’s what I was thinking since you have just tree positions on the dial instead of four. Thanks!

        • Steve Truffer

          Four position selectors are a novelty, I’ve yet to see anyone prefer them. They’d most likely replace the ratchet timer with a standard A3 group.

        • James O Donnell

          There are only 3 positions on an M16A2, M16A4 or M4: SAFE, SEMI and BURST.

          M16s, M16A1s and M16A3s have SAFE, SEMI and AUTO. Presumably it will be the same on M4A1s, and the receivers of converted M4s will have the BURST marking milled away and replaced with AUTO. Simply the reverse of what was done when M16A1s were converted to M16A2s in the 1990s.

      • Orion Q.

        The markings are all being redone to say “full” instead of “burst”.

      • matthew_carberry

        They should be shooting trigger-controlled 3-5 round bursts when firing on FA anyway, so leaving the “Burst” would be a good reminder. 🙂

    • HSR47

      No modification to the lower is strictly necessary. The original M16 was designed as a safe/semi/full auto gun: the burst mechanism is entirely drop-in (it’s basically just a toothed wheel on the right side of the hammer, and a second disconnector), so really all they have to do is put different parts in the lower.

      As far as the markings on the lower go, there’s really no practical need to change them.

      • James O Donnell

        The markings will be changed. When M16A1s were converted to M16A2s the “A1” and “AUTO” markings on the receiver were milled away and replaced with “A2” and “BURST” markings.

        When M16s were converted to M16A1s, the “A1” was added using “A” and “1” stamps.

        I can remember seeing XM16E1s that had been overhauled into standard M16A1 configuration, but I don’t recall any changes to the markings. Since the only real change was the closed flash hider and a new charging handle — which I suspect was done simply by issuing an MWO and having armorers swap the parts at the unit level — I doubt there was ever any changes to the markings. They were simply considered M16A1s and the XM16E1 markings were ignored.

    • James O Donnell

      No modifications to the receiver will be necessary, beyond milling away the “BURST” marking and replacing it with “AUTO.”

      We converted lots of M16A1s to ‘A2s and that was the only change made.

  • Rodney

    The 5.56 is a joke. While they’re re-barreling they should upgrade to the 6.8SPC…just sayin’

    • Uniform223

      The 5.56x45mm NATO still kills people. There are alot of joe taliban Al Qaeda fucktards that meet their maker because of it. Having the thicker barrel is a good idea. It holds better accuracy because thicker barrels have less muzzle whip. Also as stated it deals with heat better. I believe that the main reason for a thicker barrel was to better cope with the new M855A1 EPR.

      • Chris

        Good for killing some terrorists in the middle of desert but no so much when facing a first world country like China or Russia. Both who love trolling America after the two wars that have weakened our Armed Forces.

        • Uniform223

          Though I do not have experience with the new M855A1, battle buddies still in tell me that its dramatic overall improvement over the NATO green tips. Also the M855A1 in some areas has better hard target penetration performances exceeding the M80 NATO 7.62. The US Army is currently developing the M80A1 that will have changes identical to the current M855A1.

          • Bill

            In all fairness the green tip has a steel core penetrator while the m80 is straight ball ammo. That is to say the green tip is an actual AP round. I don’t know if it is a shell game that the brass like to play when they talk up the 5.56 round or they just send guys out to do briefings with a power-point deep level of knowledge.

            They are making the same argument with the new 855A1 as it is an actual AP round again compared to the regular ball ammo of the M80. I would like to see armor penetration tests comparing apples and apples. M855A1 versus M61. And yes I have had to carry a full combat load of M855 and M61 (we couldn’t get match rounds for the EBRs) up foreign mountains and I truly appreciate the weight difference.

          • Uniform223

            The old NATO green tips were considered a general purpose round. The steel core “penetrator” in the bullet was to give better long range performance over the older M193 which was a 55gr compared to the M855 that is a 62gr. The M855A1 EPR ( also a 62gr ) instead of having a steel core now is a two part bullet design where it has a copper base slug and an exposed steel penetrator encased in a reverse drawn copper jacket.


            The new EPR definitely has increased penetration over the older NATO green tips. The US Army considers the EPR to be general purpose, do they consider it to be a true AP round like the M995, I don’t know

    • HSR47

      6.8 is not a cartridge that can really be shoehorned into the current stock of guns.

      The primary issue is that the larger cartridge diameter, which leads to issues with both the bolt and the magwell. The only real solution to these problems is to scale the entire gun up slightly (e.g. LWRC Six8). This would require replacing the entire stock of M4 carbines with an entirely new rifle, rather than just swapping out the barrels and a few trigger components; As such, the cost would be FAR higher (figure 800-1600), and would also require a huge investment on the ammunition manufacturing side as well.

      In short, the reason that’s not happening is that the cost/benefit analysis says that it isn’t worth doing.

      • Uniform223

        You are a individual with a good head on their shoulders

    • /k/ says hi

      >Not glorious .300 Blackout
      What a scrub.

  • hydepark

    I’m wondering why they don’t throw on better muzzle brakes at the same time? My AAC one was cheap and easy to instal and time and it’s WAY more comfortable to the reduced felt recoil / muzzle rise compared to all my friend’s ARs. They are a bit noisy, though.

    • John

      Probably because A2 brakes have nothing wrong with them/no complaints about them and are extremely cost effective ~7$ on the consumer market, probably a 3-4$ part for the gov. No need to fix something that works

      • hydepark

        I think anyone who’s actually used any of the muzzle brakes like I’m talking about would say there’s a HUGE difference between them and the A2. It’s old (good, but old) technology. The new muzzle devices make follow-up shots quicker and easier, improve accuracy, etc. etc. I’d say even with the price difference there’s a lot to be gained. Maybe that’s just me.

        • Emir Parkreiner

          It is just you. The differences between the A2 and comparable muzzle brakes/flash hiders, when quantified, are marginal at best and do lnot justify government spending of that magnitude.

          • hydepark

            Hmm. Maybe one of us needs to look at those graphs a bit more closely. As far as I can see, at the far range, a %50 reduction of “rearward forces” was documented. Among other things.

            My original comment (remember folks, casual conversation here) is that if they’re going through all this trouble of barrel swaps and so forth, and have scrapped the replacement competition, why not at least look into the possibility of upgrading other important components. There’s a reason a lot of guys I see running semi-auto (and bolt, for that matter) 7.62 platforms are switching to these highly effective muzzle devices. And the added benefit of QD suppressor use is a nice bonus down the road. Turns out it’s not just me.

            And the way I see it, one of the very few responsibilities of our government is to establish and fund a military. I’d rather be buying upgraded small arms than birth control pills.

          • Emir Parkreiner

            Flash suppression is more important than a recoil reduction for an infantryman. If you look at the flash suppression, you’ll see that the A2 performs adequately for it’s cost. The reason they aren’t dropping the A2 for the flavor-of-the-week muzzle device is the same reason they didn’t replace the M4 with the SCAR-L: the benefits are not significant enough to justify the increased cost.

          • James O Donnell

            There’s no free lunch.

            All that re-directed gas is going elsewhere with a muzzle brake.

            Doing unhelpful things like deafening the soldier next to you, or kicking up dust that gives away your firing position.

            It’s a 5.56mm rifle, not an elephant gun. If the recoil is too much to handle, work on your physical fitness.

          • hydepark

            I guess the most condescending comment here wins. I was just here for some casual conversation, and end up being told that I’m a weakling because I like a certain muzzle device over another. Slow clap. I think the difficulty may lie somewhere in your failure to comprehend what I was saying. Or, most likely, you’re just more interested in looking superior to strangers on the internet. Have fun with that.

          • James O Donnell

            I’m sorry I used real-world examples of the problems with your boutique muzzle brake.

            Maybe this will be a better-fitting comment: you are a thin-skinned little child who doesn’t like it when someone points out an obvious flaw in his fanboy-thinking.

          • Uniform223

            I am going to have to agree with sticking with the A2 flash suppressor.
            I have seen muzzle brakes and compensators become too much of a crutch for “tactical” shooters. I’ve even seen people get a brand spanking new AR-15 and ditch the A2 ( that have no prior experience with them ) and immediately replace it with a compensator or muzzle brake. Those devices do not teach nor do they reinforce the some of the basic fundamentals of marksmenship ( stance, how you hold your rifle, trigger control ). They a mediocre shot become a good one. I am not gonna bash on your physical performance ( though seriously if you cant handle the recoil of a 5.56 you gotta work on something ) I will agree that compensators and muzzle brakes ( unless you’re using heavy/large caliber weapons ) are not useful for the average joe marine/soldier.

          • Dan Atwater

            Not to mention that flash suppression is far more important than recoil mitigation in this context.

    • RawDawg

      Lets not forget that some soldiers couldn’t hit a lake with a shotgun if they were sitting on the bottom of it.

  • 101nomad

    Old time bias, I would rather have a reliable rifle than body armor. (Gonna catch hell for that).

  • bbmg

    These minute improvements are good for grunt morale but not much else, the outcome of modern conflict is not decided by the quality of infantry rifles but by superiority in terms of air power and artillery.

    • RawDawg

      Except that no war can be won without boots on the ground.

    • Ben M

      Yeah, about that… $120 million is a laughably small amount compared to the $12.5 billion annual program costs for the Joint Strike Fighter program. It will be $1.1 Trillion when its all said and done, about 10,000 times the cost of this upgrade. The cheapest per unit cost is $124.8 million for the F35A… so which would you rather have- upgraded small arms for 500k of America’s finest, or one more F35 (minus a few million in parts)? IMO if the M4A1 upgrade saves even just one American life, the decision is simple.

  • Ted

    Looking at all those monkeys in the shop – no wonder the m4 fails so often.

    • CA

      I can’t believe who is assembling the firearms. -_-

      • Travis

        What exactly is wrong with them to make them not meet your stringent standards of quality? I’m sure we’d all love your insight here.

    • Geodkyt


      What, pray tell, VISUALLY distinguishes these workers from workers in any assembly process? It’s not like they’re building a satellite to clean room specs, nor is there any need for them to be in uniform coveralls like they’re diesel mechanics.

      In fact, that collection of people could just as easily been a shot of the Navy rocket scientists (literally) I work with, absent the M4s in their hands.

      • matthew_carberry

        Racist troll is racist.

  • CA

    What contour barrel are they going for? Heavy contour is absurd. It’s so front-heavy! 3-round burst is an insult to the military. “You’re too stupid to handle full-auto, so you get this instead.” You can’t cancel the burst right away, so you’re locked in. That extra round or 2 you fire, that you don’t feel you need when dealing with multiple close targets, well you’re forced to serve it, and that can get you killed.

    • HSR47

      Actually, the burst fire control group (FCG) on the M16 does NOT keep the rifle firing after the user has released the trigger.

      With a full-auto FCG, the disconnector only grabs the hammer when you release the trigger. With a burst FCG, there are two disconnectors: the left disconnector functions exactly as the single disconnector in an auto FCG (it stops the rifle if you release the trigger), while the right one has two hooks (one to grab the hammer, and one to interface with the burst cam riding on the hammer pin between the hammer and the right side of the receiver {which has two burst sequences, each with two shallow notches and a deeper stop notch}).

      TLDR: A full-auto FCG set to “auto” will stop firing if you release the trigger, while a burst FCG set to “burst” will stop firing either when you release the trigger or the second/right disconnector rides into the “stop” notch. Since the cam wheel rotates one slot every time the hammer cycles, that means that each burst will fire 1-3 rounds.

  • RawDawg

    Full auto on the riflemans carbine is not necessary over burst in any scenario. You won’t put effective fire on a target with one smooth full auto trigger pull over racking off multiple bursts with burst. Burst also helps really shitty shots in close up scenarios with the utilization of 2 extra bullets vs 29. You put your most competent people on the SAW for a reason. It’s the MCPW. Everyone with full auto is just going to result in more wasted ammo, which the government already chastises soldiers for. This just looks like someone finally got a promotion and wants to waste more money on their personal opinion.

    • HSR47

      First, the burst trigger group was only shoehorned into the M16 because some group of generals decided that it would be easier than training solders proper trigger discipline.

      Second, because the AR10 (and consequently the AR15/M16) was not originally designed to have a safe/semi/burst trigger group, one was shoehorned into the platform. As such, it is entirely a kluge.

      With the full auto fire control group (FCG), the auto setting just pushes the disconnector down (so that it doesn’t grab the hammer), and pushes the auto sear into position. When the rifle is fired, the bolt drives the hammer down, the hook on the back side of the hammer is caught by the autosear, and then released when the bolt carrier strikes the autosear.

      For the most part, the burst FCG it’s just like a full-auto FCG, except that it has a ratchet wheel that rides on the hammer pin (on the right side of the hammer), as well as a second disconnector with two hooks (one for the ratchet wheel, one to grab the hammer). The ratchet wheel has a total of six faces (two shallow teeth then a deep tooth, another two shallow teeth, and then a final deep tooth); when the extra disconnector falls into the deep groove, it moves forward enough for the rear hook to grab the hammer (thus stopping the rifle from firing).

      There are two issues with this setup:

      *The burst mechanism effects the trigger pull (read: makes it inconsistent), which has a negative effect on accuracy.

      *The gear advances one tooth per round fired, thus meaning that firing set to “3 round burst) can easily result in firing only 1-2 rounds.

      In short, the full-auto trigger group is better because it makes shooting accurately at distance far easier (a consistent trigger is far better than an inconsistent trigger), and it makes close-in support/suppressing fire much more practical. The only real cost is the need for slightly better training. The M16 burst FCG has always been a political boondoggle, and the sooner it is condemned to the dustbin of history, the better we will all be.

    • matthew_carberry

      Burst was a clunky mechanical solution to a training problem. Properly trained troops will still end up shooting 3-5 round bursts on FA out of the rifle, when needed, same as with the SAW, but will have a much better Semi pull for making well-aimed shots.

  • MattInTheCouv

    I’m an AF guy who doesn’t have a cool enough job to have an M4, so we shoot M16-A2’s at qualification, which have had AUTO markings ground down, and BURST etched in behind it. The thought of the AF following the army on this, and re-reworking guns back to AUTO from BURST, and having the BURST ground down and them trying to find room to re-etch AUTO back onto the lower receiver made me chuckle.

  • Steve_7

    Sounds like a: “make work” program to me, what is the point given the pull-out?
    Having used M4 carbines on full-auto, I couldn’t hit a blessed thing after the third round came out of the barrel past about 7 yards. When I get to the fourth round, it feels like someone is banging a pile driver into my shoulder. No doubt with all their gear on it wouldn’t be so bad but I fail to see the point, you can provide suppressive fire on semi-auto let alone full-auto.

  • Will

    Let me get this straight:
    In 1999, when I retired, ALL M-16s, no matter what the model, had a three position selector switch. Position three was full auto. What happened? I know we went through that POS three round burst trigger group but now all M-4s are semi auto only? Were the troops wasting ammo, in fire fights, that we would have sent our Midfleastern “Allies”?
    Why not just leave them all full auto capable and teach fire discline and ammo conservation? Oh, and marksmanship.

    $120M to correct a screw up that caused the screw up???
    There has GOT to be a politician deep in the middle of THIS BOONDOGGLE!!!!!


  • Secundius

    Why would you need suppression fire on a deer hunt, If you can’t kill a deer with one round, twenty or thirty rounds going down range, isn’t going to do you any better, with the exception of eviscerating the deer. It kinda defeats the purpose of the hunt, doesn’t it.