Upgrade for M4 in 2011: New Barrel, Bolt and Rail

Army.mil reports

Col. Douglas Tamilio, program manager for Soldier Weapons, said the Army will do a request for proposal in the next three or four months to complete the Army’s acquisition objective for M4 rifles. That RFP will include more than 14,000 M4A1 rifles — an improvement over the M4 Soldiers currently use.

“What the M4A1 gives our Soldiers is a heavy barrel and fully automatic — that’s what the field is asking for,” Tamilio said. The M4A1 also features ambidextrous controls.

The Army already has a contract with Colt to produce the rifles. The second contract, in the next fiscal quarter, will help the Army complete its AAO and will include additional rifles for both foreign military sales and to meet other Army requirements. Tamilio also said the Army will work a contract to procure some 65,000 kits in FY 2011 to convert M4s already in the field to the M4A1.

Other phases of M4 improvement involve a better bolt and rail.

“I think we can get significant increases in reliability by looking at some new enhancements to bolts,” Tamilio said. “Because a lot of companies have shown some bolts over the last year or so that have got, we think, improvement. We’re going to ask industry to give us their best.”

[ Many thanks to Lance for emailing me the link. ]

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.


  • leopard

    Colt’s own RIS for the M4? And does ambi controls mean they will include Norgon mag catch like the USMC SAM-Rs?

  • Sounds reasonable to me

  • sadlerbw

    I wonder if, by an improved bolt, they means something like the AR15 Performance super bolt or the JP Enhanced Bolt, or something entirely different. Both of those are supposed to have stronger locking lugs and cam pin holes, but there are plenty of other bolts out there that just have different platings to make cleaning easier, and I’m sure there are bolts/barrel extensions out there that are even more radically different. It seems like, in many of these competitions, they already have some idea what they want to see, and I’m just wondering how far they want to go in mucking with the bolt.

  • Spiff

    How many changes to the M-16/4 does this make? 100th? Next one probably due in about 6 months…

  • On a side note, the Army has issued solicitations to FN Manufacturing to make certain M4-specific replacement parts.

    • Daniel, thanks for the info.

  • Vitor

    I wonder what improved bolt it is…my bets would be the KAC E3 bolt.

  • Matt

    Rediculous. New bolts to fix a reliability problem caused by magazines. Idiots. Buy mags that work and you won’t need any bolts that “we think, show improvement.”

  • Lance

    They forgot the piston conversion kit. I think the improved bolt will be a major upgrade and improvement to the carbine. This program will last till 2010-2013 then the army may covert all M-4s to this new standard.

  • jdun1911

    GI magazine works and unlike Pmag they have no trouble fitting on standard GI pouch. There was a somewhat large argument between Marines and Magpul reps on Arfcom. Magpul wanted the Marines to change their magazine pouches. The Marines wanted Magpul to change the floor plate which is what causing the troubles.

    The problem stem from over used magazines that went pass its life cycle. That happen in any magazines GI, Pmag, Lancer, etc. One of my Black Dog .22lr magazine which has well over 10,000 rounds in it was giving me trouble last time at the range. Second to the last round, it was causing bolt override constantly. I ordered some new springs hopefully that will fix it, if not I’ll dump it in the worn out magazine box section.

    Unlike many military firearms, the AR15 is constantly upgraded. In a few years both ACR and SCAR will be outdated because there is no third parties support. It is the strongest selling point to keep using the AR15. No other rifle/carbine has that much support in the industry.

    The upgraded bolt will be Nickel Boron coated is my best bet. It also could be KAC E3 with Nickel Boron coat.

  • ki

    It’s not really an upgrade. They’re just issuing to regulars what SF have long been using.

  • ermac

    Really? Fully automatic? I thought the army thought that fully automatic was pointless in an infantry rifle. I wonder if it will have a heavier buffer to reduce the rate of fire? The current M4A1’s have a pretty excessive rate of fire. A buffer to reduce the ROF to 450-600 would be acceptable.

  • Lance

    Im with Jdun1911 on this the modularbilty on the M-4 and M-16 is far longer lasting due to that every one here in the US make AR parts and accessories and makes improvements on it. no other weapon has so many varations and differt accessories.

    The only other military rifle ever to be so variante is the AK-47/AK-74. But they dont have as many refinements and accessories either.

    I cant wait to see what the final Army improved M-4 will look like and feature in late 2011 and 2012.

  • charles222

    Pmags do work with the standard pouch. I know this because I own eight of them and and I’m an 11-B. So unless the Marines are rolling with a completely different pouch, this is a moot point.

    Moving on: The piston is completely pointless unless you’re planning to roll with a sub-11-inch barrel and a suppressor. No need whatsoever, and you’ll harm accuracy.

    I’m rather curious about the “improved bolt” as well. I’m guessing stronger extractor springs-there was an article by an AWG rep last year sometime on Defense Review that detailed that alot of malfunctions due to weak/old extractor springs.

  • Keith Applegate

    It IS a fact! There are SOME dual mag pouches that don’t work well with P-Mags. The often encountered MOLLE II pouches made by Specialty Defense are the most common culprits. Two 30 round USGI magazines are a tight fit in them.

    The same goes for the MOLLE II three pocket/six magazine bandoleers that snap into the pack. They are made to be a tight fit on USGI aluminium magazines and anything slightly bigger in any dimension simply will not fit and still close properly.

    Now if you are using a pouch made by Tactical Tailor or several other private companies P-Mags will fit fine.

    The funny thing is that the original vietnam era ALICE 30 round mag pouch that held three magazines will work just fine with P-Mags. They will even hold P-Mags with the lid in place.

  • jdun1911

    Marines use different pouches. While Pmag can fit in Marines pouches it does take some effort. The problem like I posted is Pmag/Emag floor plate that is wider than the standard GI magazine. This is the main reason why Pmag/Emag isn’t wildly adapted in the US military.

  • Vitor

    Ermac, no way a DI gun with carbine lenght gas port can have a rate of fire of 600 or less. If it’s gets to 750, it’s already quite good.

  • Stella

    Since when has the metric by which a firearm is judged been how many do-dads are made for it? I don’t see how the SCAR, ACR, XCR or, for that matter, the older FAL, AK, M1, M1A, G3 etc. can be rendered obsolete because they lack the same obscene variety of, say, ergonomic pistol grips or new, infinitesimally modified bolts that are likely snake oil dressed as magnetically inspected metal.

    I imagine if the SCAR, ACR, or whatever else becomes as popular as the AR platform they will also have the same plethora of aftermarket stuff. I also imagine that if they were adopted by an institution as intractable and reactionary as the United States military they would have also received dozens of workarounds for their various shortcomings rather than being replaced. Then again, perhaps they don’t need all that crap.

  • Lance


    Sorry I disagree I dont see the FN or ACR doing mucvh better since noone is useing them.

  • jdun1911

    I did not said they are obsolete. I said “outdated”. Outdated does not mean obsolete. I made sure I use the word outdated and not obsolete. It actually took me a while to find the right word on that post.

    SKS are outdated but still effective. However there are better choices out there, right? Right. Musket are obsolete. They can’t complete in the modern battle field.

    Because of the changing military environment and newer technology that comes out, firearms that can’t adopted due to lack of third party support will fail. For example, because of the urban setting, contractors in Iraq wanted more flexibility with their sling. While AR15 didn’t invent the single point mount it was very easy for third parties to provide it for the operators in a fast maner.

    Unlike the AR15, SCAR and ACR are proprietary platform and expensive. Because of those two constraint I doubt it will attract a large third party following. SCAR been out for sometime now. How many third parties support the carbine?

  • jdun1911

    The ACR and SCAR has all the crap that the AR15 already had that is not platform centric. Just a few years later.

  • Rijoenpial


    fact check: the AR15 has more than 50 years, and hundreds of replicas from more than 20 companies…It is a design exploited ad nauseam…

    The SCAR has 2 years!! Oh, and it is only used by SOCOM so far! Like the M4 was before being issued to the Reg Arm… And that was like 20 years ago!

    So, have an Army use it, and all companies will plunge into it! Supply and demand!

    So, the Ar15 is an obsolete design that is only still breathing because of buyouts, payoffs, and a lot of corruption amidst the USArmy! Only that explains why truckloads of M4s are STILL being bought!

    The M4 limitations are well known…the SCAR has perks the M4 doesn’t…

    These are mere upgrades that try feebly disguise what is the real prob: the ammo, more specifically, the 5,56×45…

    That prob not even the SCAR can disguise…!


  • Rob

    Who’s making the rail system? DD? KAC?

    Sidenote- I believe Emags solved the problem of the mags being too thick. THey’re windowed now too, so it shouldn’t be an issue. If the bolt was the KAC design- that’d be frackin awesome.

  • charles222

    The same goes for the MOLLE II three pocket/six magazine bandoleers that snap into the pack. They are made to be a tight fit on USGI aluminium magazines and anything slightly bigger in any dimension simply will not fit and still close properly.

    This is kinda hilarious, as I’ve gotten P-Mags to fit in exactly these. 😉

  • Lance

    For work I have both a Molly pistol pouch and a LC2 M-16 mag pouch. I dislike Molle alot. The LC2 pouch can hold both GI and Pmags.