Remington ACR multiple lower receivers

One aspect of the Remington ACR which I have not seen discussed online is that it is being offered by the company with a variety of lower receiver designs.

From the Remington Military catalog.

The standard Bushmaster / Remington ACR receiver is made of polymer with a moulded pistol grip. Remington is also offering another lower receiver that can accommodate an AR-15 pistol grip. See the above image.

An employee of Remington MPD told me that they also plan on offering a magnesium alloy receiver to select customers. I suspect that Remington would be willing to offer a lower receiver made out of diamond encrusted platinum if a large enough military customer required it!

If the Bushmaster ACR sells well, aftermarket lower receivers could bring in a lot of additional revenue. More than a few customers would be willing to hand over fistfuls of cash for a fancy all-metal lower receiver so that they could differentiate themselves from the crowd.

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.


  • SpudGun

    An AR-15 pistol grip? I thought the first thing AR buyers did when they got a rifle was swap out the standard grip for a Magpul grip.

    I suppose the first question is – are these AR grips moulded into the lower receiver as a solid piece or can other aftermarket pistol grips be swapped in and out?

    My next question is – how much are Bush-Shyster going to be charging for this small change in plastics?

    The final question is – why am I even bothering asking about this rifle, I’ve gone beyond caring.

    • SpudGun, the pistol grip is just part of the mold. I can’t remember why Magpul went this route originally with the Masada.

  • George Lawrence

    Looking at the picture it actually appears that one with the AR grip is configurable in that you can swap the pistol grip with any standard AR grip and the same with the trigger guard. For me at least this certainly makes this rifle a lot more interesting.

  • George Lawrence

    In addition, the magwell looks to be more flared probably making for a cleaner mag change, just a shame they cant do all that on the base rifle.

    • George, I did not notice that. It does appear to be flared

  • Carl

    Why would anyone need a “magnesium receiver”? Is there something wrong with the default one?

  • Maigo

    It must just be a different revision they grabbed for the photo op, cause there’s a LOT different between the two

  • “Why would anyone need a “magnesium receiver”? Is there something wrong with the default one?”

    Polymer receivers can have problems with heat buildup. It’s one of the things that killed the XM8 carbine.

  • Redchrome

    Because some people just have to be different, that’s why. 😉

    Personally, I’ll get interested in the ACR when they make a lower that takes AK mags or some other mag (G36?) that isn’t broken by design like AR mags. I’ve seen a picture of an early Masada with what was claimed to be a magazine of Magpul’s own design; but it looked to me like an 5.56mm AK mag stuck in an AK magwell on an 5.56-bolted upper. Dunno if it actually worked or was just arranged for photographic purposes. 🙂

    A rifle magazine has not yet been built, which incorporates *all* of the best-practices features that I know of. At least not that I’ve ever seen.

    Also, when will there be a .22LR conversion for the ACR? That’s another thing to look forward to. 🙂

  • KalashniKEV

    Sooooo… the other reciever is that you can put on an aftermarket AR pistol grip!?!?!?

    I was expecting to see an AK type lower, an Uzi mag lower, a greasegun mag lower.

    This thing just keep sucking more and more…

  • David

    Forget the ACR and buy yourself a Robinson XCR. Actually, you could buy two XCR’s for the price of the Bushmaster. (almost)

  • Big Daddy

    It looks like they might be trying to correct little issues that Magpul did not.

    What their final goal for this weapon is kind of unclear to me. Is it a superior AR type platform to compete with the SCAR and others? Or is it coming into a final configuration for mass production/sales? Or is it just a rifle that can be configured any way the buyer wants, military/LE or civilian? Or is this an evolutionary process to try and make it the weapon to compete with the Colt M-4/M-16 family for a huge buy in the future from the DOD especially the Marines?

    At first it looked like a good well thought out weapon that would fix so many of the issues of the AR platforms and other weapons like the G36 the DOD rejected. I never understood the whole H&K type lower receiver with the molded in pistol grip, that was 5 steps ahead and 3 back with this weapon. Maybe this is the fix……..

    Whatever it is they missed out on the biggest gun buying spree in history from the American public. Maybe there is some truth to the claims from some about the present administration going after the gun owners of America and there will be another huge buy from the public. Who knows…….especailly now with the militia issues.

    But what I do know and contrary to some so called experts neither the standard AR platform of gas impingement nor the so-called “FIX” of making it a piston gun is the answer for the military. Neither is the 5.56mm round for that matter. IMO.

    I was a soldier and if I were to go to battle I would want a piston weapon, easy to care for, short(16″ barrel), accurate to 500 meters, reliable and with a round that would shoot through something and be able to knock someone down and/or kill him. Yet be a little smaller than the 7.62mm which is a bit of overkill for a modern battle rifle considering the proven data from battle fields all over the world since WWII.

    So I just off hand wonder exactly what Remington is thinking in terms of this weapon. I would think making money is #1, but in what market place.

  • allen

    The black grip is a Magpul MIAD, configured to look like an A2 grip. The black trigger guard is Magpul too.

  • charlie taylor

    Looks like the AR-15 receiver takes AR-15 trigger packs as well. Look, there are pins and everything! So maybe bushmaster/remington didn’t abandon the idea of the ACR taking AR-15 trigger packs!

  • DavidR

    That doesn’t look like a standard AR pistol grip but rather a black, Magpul MIAD w/ finger groove insert. So you can probably swap out the back straps and the front straps…probably…

  • Brian

    That’s not a standard AR grip, that’s a Magpul MIAD in black.

    Carl, the standard receiver is plastic. Some people are uncomfortable with their “zombie killer tacti-awesome assault rifle” is made of the same stuff as a kid’s toy gun.

    • Guys, I just meant you could swap in any AR-15 grip.

  • Nill

    Considering that the fire control group pins are visible on the exterior of this “AR” gripped lower, I would venture what’s pictured actually IS the alloy lower.

    If it was just another poly lower why wouldn’t it be using the same drop-in trigger group as the default lower?

    That would also explain why it uses separate grips and trigger guards, as including such things on a forging would raise costs exponentially for little gain, unlike on the polymer lower where a one-piece design actually lowers costs and improves structural rigidity.

    • Nill, well spotted!

  • R.A.W.

    Now when are they going to start offering those AK compatible mag wells that were shown off with the Masada?

  • Frank

    magnesium? Isn’t that a bit hazardous?

  • Other Steve


    Magnesium is lighter than aluminum and most often stronger too (comparing common alloys when forged).

    It does however, have a nasty habit of being a very efficient fuel and is more expensive then Al.

    Methinks the ACR is a piggy and they know it. 8.3lbs with an M4 barrel is pretty bad. They are probably at the point where stepping up to better plastics is outweighed by moving over to metal forgings (ironic really).

  • Other Steve

    This is all ofcourse even MORE reason NOT to buy an ACR right now! Even the “enhanced version” will probably need a lower change out at some point unless they nailed the ergonomics for all users right out the gate, which they did not.

    A 2010 ACR I gather will be quite a bit different than a 2011 ACR. The latter being the one to get.

  • Armageddon Rex


    I’m sure it won’t be a “magnesium” receiver. It will be an Aluminium-Magnesium alloy receiver.

    Aluminum-Magnesium alloys are much stronger and more ridgid than either Aluminium or Magnesium alone. They also weight less than aluminium.

    The problem with even extremely high quality petroleum based plastics is that they suffer slow but unstoppable degradation from heat and / or sunlight over time.

    Leave a polymer ACR receiver out on a rock on a mountain in Southern Afghanistan for 10 years, and when you come back and test it you will find it is more brittle and less strong than a new unit.

    A receiver made from the proper aluminium-magnesium alloy will be stronger than new because of work-hardening inherent in the heat cool cycle.

    Polymers only become weaker upon exposure to moderate heat energy. Most semiautomatic rifles I’ve fired do become warm once in a while;}

    Properly designed metal parts of the correct alloy are generally undamaged by heat.

  • Josh

    I read on the Bushmaster ACR Q&A someplace that you would have to swap lowers if you wanted to run 7.62×39 in it.

  • BTR

    How ’bout that reciever to take AK mags in 7.62×39? Saw an early photo, would like to know if it will make production.

  • D

    maybe some customers are still edgy about using a polymer lower…despite glocks and stuff having wide circulation.

  • D

    I have the feeling the receiver on the right side is the magnesium one since the stipling is gone, and the fact that there are AR15 style grips on it. I think its risky making a swappable grip on a plastic lower, youre just asking those threads to get stripped out when you have a metal bolt.

  • slntax

    what? more overpriced bs ….. i hope they fix up the XCR short commings and then ill be in line to buy one.

  • Steven

    Carl, what kind of theory is that? Chrome-moly steel, aluminum and magnesium all have advantages and disadvantages as alloys for receivers. One isn’t always better than another — see the decisions around alloy wheels in auto racing for a good comparison.

  • Josh

    slntax – i’m all over the XCR as soon as they get the new Butt stock!

  • Nadnerbus

    I was flabbergasted when I saw the standard rifle would come with a fixed, molded grip. For a rifle billed as the most customizable thing ever created for the ubber war fighting mega man, having a standard fixed pistol grip seemed ridiculous. Especially when you consider that they would stand to get Magpul a lot of business with replacement grips. Sure plastic threads would strip. That’s why you put a threaded steel insert into the poly for the grip screw.

    I suppose maybe there was a good technical reason not to do this on the poly lower, but it just seems like bad judgment to me.

  • Nice find Steve!

    I’ve heard rumors of a lower that accepts AK-47 mags, but never seen one. I’ve never heard of a lower that takes regular AR-15 grips.

    After the price, what bugged me most about the design is that one-size-fits-some integral grip. My hands are on the large size, and I have a hard time getting the right trigger reach.

    • Suburban, the Masada was supposed to be available in 7.62×39. I do not remember Bushmaster saying anything about it.

  • Special run of the ACR with designation “ACR Supertactical-0104”?:-)) With the selector lever 0-1-APR?


  • Carl

    Well, leaving aside the discussion about the ultimate material to make weapons out of…IF the plastic receiver indeed has issues, then that sort of reflects badly on the standard gun.

    And IF the magnesium-aluminium (or whatever) receiver is only to appease people with irrational phobias about plastics, then that seems like a perfect way to screw up your reputation as a serious gun maker.

    Either way, it doesn’t inspire confidence, IMHO.

  • Azriel

    Here’s the thing… There’s no real point in worrying about lowers and uppers and the whole damn gun when there’s no gun to try out and make fact-based opinions on. Wait till BFI/Remington actually release this stuff to the public and give it a try before actually complaining about how it doesn’t work at all.

  • D

    militaries might not have approved plastic lowers yet, so one reason why they are offering metal lowers

    “I suppose maybe there was a good technical reason not to do this on the poly lower, but it just seems like bad judgment to me.”

    I would think a plastic lower with a metal screwing in a plastic grip is really risky. Youre just asking to strip/pull out plastic threads with that setup. Hence why the swappable grip is only on the metal receiver.

  • Whatever

    I wonder why nobody makes their new assault rifle designs out of steel? I guess for me it would be more important to have a reliable and durable battle rifle than one that managed to shave off as much weight as possible.

    Given that these rifles have moved from being inexpensive tools into expensive ones, I’m surprised no one is making receivers out of titanium just for the extra ‘Wow’ factor.

  • Canthros

    Frank: A pure magnesium receiver might be potentially dangerous, it will probably be made of a magnesium alloy. While different alloys will have different properties, there is at least one magnesium alloy that doesn’t burn well at all.

  • d

    titanium is really expensive to machine, you have to have a special machine to work it. Steel would be too heavy of a weapon if aluminum wasn’t utilized. A steel frame 1911 weighs noticeably more than a aluminum frame 1911, so imagine and entire rifle. No ones having problems with aluminum lowers and uppers.

  • zach

    I believe the Masada, not sure about the bushmaster gun, was configured so that it could take AK mags, obviously with correct bolt and barrel of course. I think it would be a great idea to market metal receivers for this gun, because let’s face it some people like steel, and I’ve never been a fan of most polymer guns, like those Cav Arms polymer lowers, they were ugly, you can’t swap stocks, it goes on. but the ACR receiver is pretty decent

  • Alex B

    This lower is a big plus for me, as i found over the years that there is no “one-size-fits-all” perfectly some will prefer the single “finger grove style” (A2) and some just see no way to have your ar15 without fancy
    rubber-touch coated, super-uber ergonomic grip.

    Well this is mostly a choice thing, personally i always found it hard to find a proper shaped\sized grip for my small hands, and those finger groves do come in handy with sweaty hand.

    I can see why they had the single-body, but no matter how hard the lower will be plastic does breaks over time (cracks, chips and deep scratches) and lets face it when it comes to costs a grip is way cheaper then a lower.

    I think that army markets will prefer this lower option over the standard one

  • d
  • d

    AIM has sold 17 of the 20 they received

    I just saw a post on that addresses the “proprietary barrel”

    “The barrel may end up proprietary, but starts out as something fairly standard.

    Here I’ve overlayed a mid-length barrel and M4 style barrel onto omd’s photograph for comparison.

    As you can see, at its core an ACR barrel amounts to a mid-length barrel with an added M4 cut. A simple enough change that any barrel supplier could accommodate.

    Where it gets proprietary is when you factor in the second gas port, specialized barrel nut, and spacer.

    I would go so far as to say you could likely take a stock mid-length AR barrel and adapt it into an exact match, as long as you’re willing to cannibalize an existing ACR for the mounting hardware and piston.”

  • DaMan

    every critizim made about this gun is true. but i still want one. and im pretty sure thats why its still a huge topic of discussion because everyone else wants one too. we more thrift buyers are just gonna have to wait till the package is acceptable. that being said you could have a SL8 situation where they put the gun out and no changes or after market parts come out and people end up fully modding the gun to get what they want. or you could have a sig 556 situation where it come out in a way i hated and eventually they put out a version im looking for(sig 556 classic) and the price came down to boot. so its all a gamble….i really really hope remington, bushmaster and <> support this gun with different grips, stocks, lower receivers, barrels, and so on. that was promised. also a kit like MSAR would be great too.

  • Tom Stone

    I hope the lack of recent posts means steve is shacked up with Angelina Jolie.

  • Travis

    Yeah, this design choice never made sense. The ACR is supposed to be, like, “the most adaptable rifle ever”….yet the pistol grip is molded as part of the lower receiver?