Modular Rifles: A Tale of Two Patents

Posted in AR-15, Rifles by with 20 Comments
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pat_7810271_1-tm-tfb

Last month Bushmaster was awarded a patent (#7810271) for an AR-15 (or AR-10) compatible modular rifle system. The patent proposes using a mag well that can be removed from the lower receiver. The mag well could be any conceivable length in order to accommodate special upper receivers. In theory, cartridges as big as the a .338 Lapua could be used with this system.

Bushmaster Patent #7810271

While this patent is interesting, what makes it even more interesting is that back in 2006 Colt Defense was awarded a patent for a similar concept.

Colt Defense Patent #7131228

Solider System dug up the Colt patent when we were all trying to work out what Colt’s upcoming modular rifle would look like. The Colt Modular Carbine CM901 has since been unveiled and we know that it does not make use of a detachable magwell.

It will be interesting to see if Bushmaster run with this concept.

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.

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  • Raph84

    Not sure how similar this is to the Bushmaster or Colt, but I know the MGI Hydra http://www.mgi-military.com/index.php?id=2&sub_id=24 has been around for a long while too (I used to drool over the ads in shotgun news)

  • dt

    Doesn’t anyone at Colt or Bushmaster remember the Cobb MCR?

  • http://www.tactilite.com Michael B.

    Raph84, you beat me to it! It’s nice to see the good civil servants at the USPTO aren’t working too hard in reviewing claims.

  • Gunnar

    The rifle in Bushmaster’s patent application looks exactly like a Cobb MCR:
    http://www.securityarms.com/20010315/galleryfiles/2900/2993.htm
    Which is hardly surprising since Bushmaster bought Cobb Manufacturing a few years ago.
    BTW: Cobb MCR was available in .338 Lapua Magnum.

  • Gunnar

    The drawing of the rifle in Bushmaster’s patent application looks exactly like a Cobb MCR:
    http://www.securityarms.com/20010315/galleryfiles/2900/2993.htm
    Which shouldn’t come as a surprise sine Bushmaster bought Cobb Manufacturing a few years ago.
    BTW: Cobb MCR was available in .338 Lapua Magnum.

  • MarkM

    If any length cartridge will work, then the bolt face has a fixed depth it must cycle to in order to pick up the longest case. It basically makes it an AR10 length action cycle regardless of the actual OAL of the cartridge. That would possibly have a slight slowing affect on the cycling, and creates a longer receiver that may be slightly heavier.

    What seems to be assumed is that a major buyer wants to shoot two different length cartridges in the same gun, and that the engineering will be cost effective. There’s no previous historical success for that.

    The swappable mag well means one designed specifically for mags that accommodate case taper could be used. Not only the AK, but correctly curved 30 round 5.56 would be possible. It’s been a continuing reliability problem with the AR, as the flimsy straight mag well feed has prompted redesigns, short loading, and alternative materials for decades. It’s good to see the mag well getting attention, it’s one of the major areas of concern in reliability.

  • TracerTong

    >Soldier
    >Solider

    WHYYY?????

  • scott

    what about the MGI military modular detachable magwell carbine which has been on the market for a few years already?
    As long as they don’t pretend this is a NEW idea when they start advertising…
    BTW from what I’ve seen so far the MGI version is much nicer than the others.

  • Tahoe

    The MGI was the first thing that came to my mind, too. Granted, I’ve never met someone who had one, or had used one, nor have I even read a good review of one…but it’s a cool idea :)

  • John

    Looks more versitile than the colt, but I am thinking colt scrapped it for a reason. Anyone else care to chime in?

  • Vitor

    This whole patent system makes me sick, really. Good for lawyers, horrible for consumers.

  • Frank

    Now all we need is for someone to make a .416 Rigby upper.

  • Lance

    With the Army looking to upgrade more than replace this might be Colt and Bushmasters attempt to fin middle ground with the Military.

    Agree Jdun1911

  • Jdun1911

    Lance,

    It won’t be Bushmaster. The magwell change is a good idea if it allows the operator to move to a larger caliber. For example 5.56 to 7.62 but not the other way around.

  • http://www.unclejohnstech.com hojo

    My concern is that having the lower in 2 pieces might negatively impact overall rigidity. In particular, the short distance that the barrel/upper have to couple to the lower now. Shorter equals greater mechanical advantage applied to the grip and stock by the barrels motion. Maybe they’ve worked all this out… I’d just build an AR-10.

    Hey, here’s something totally unrelated;

    Anybody have any practical experience with the AR-5.7 (FN 5.7×28) upper? Seems like it would be a pretty wicked carbine, although I don’t entirely relish the idea of trading a locked breech gas action for a blowback pistol action. I do however love the idea of have 50 rounds in a clear magazine, visible from a shooting position.

  • Martin (M)

    You know, why don’t they just make the magwell part of the upper instead of the lower. Then the fire control group is still serialized, and you can swap to any caliber you want.

    Damn, there goes all my royalties.

  • Lance

    I agree with some that a seaprate magwell may make the weapon more brittle and prone to break the Colt sulution is better have a insert for a AR-10 mag well that can use 5.56 mags then.

    JDUN1911
    What i mean in general for a new military weapon in a era of cutbacks and fact colt is building new M-4A1s for the army as a new M-4. The best hopes for for those who demand a new weapon is a modular M-16 that be turn into a M-4 or M-110.

  • TalbotFarwell

    Could this help me realize my dream of an AR in .30-06?

    :D

  • scott

    Honestly the whole situation confuses me. I still don’t understand the hatred for bullpups. And this is coming from someone who shoots lefty! the bullpups I can operate (without a kevlar face mask and xanax so I don’t flinch when the rounds bounce off my forehead) are great in my personal opinion. Especially with variety of situations we see our military in now (urban combat in iraq need short rifle so they issue m4. Then afghanistan wide open ranges and the only guys not cursing their rifles are the marines who are still using A4′s but they hate theirs in iraq!)

    If we had a bullpup we could issue nothing but 20 inch barreled weapons with m4 OAL. Then again I could just be lucky in bullpups magazine change issues are not a big deal for me because I’m left eye dominant so I learned to shoot from my weak hand (I shoot lefty but right hand is my strong hand) so the mag gymnastics are very subdued for me. Or maybe I’m just so used to having to deal with guns not meant for lefties that my opinion is a terrible benchmark period lol

  • TXTrenton

    I have an MGI Hydra in 7.62×39, with both the AK47 and AR magwells. This means that by changing barrels and mags (and bolts, in some cases) I have one rifle that can shoot .22LR, 5.45, 5.56, 6.5, 6.8, and 7.62×39. I was concerned about the lower being weakened by being a 2-piece assembly also – but MGI has engineered the removable mag wells with enough material that I no longer worry about that factor. The one drawback is that the additional material on the MGI lower in the AR configuration makes the magazine release slightly more difficult to manipulate.

    My concern with the colt design is that there appears to be a space lect in front of the magazine in 5.56 configuration that could colledt dirt and debris – and that the 5.56 mag is not fully supported as with the current M4 design.