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Thread: THE TDP and how its possible to follow without access.

  1. #11
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    Commercial AR's can be manufactured to meet, or exceed military specs, and even some far short of those specs, but lacking a govt. inspection, they are not military.

  2. #12
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    We follow the finish on the selectors, we had had to change many dimensions of the milspec because they simply don't make sense for a semi auto AR, or would cause compatibility issues with aftermarket products.

    Things we had to change:
    1. Detent groove (M16 selector groove goes 360 degrees, can't do that on a semi auto selector. On our M16 selector, the groove goes 180 degrees only, on the semi auto, 90 degrees) In addition, ours are slightly deeper. the shoulder of the groove angle is changed, to prevent the user from backing out the selector by rotating it to 45 degrees, also to provide better detent to groove mating interface.

    2. Detent holes (milspec holes are made for M16 selectors, they will allow the selector to over rotate if the receiver doesn't have selector stops, or has a selector lever on the right side only). In addition, the geometry of the "ramp" and width of the holes are changed, to reduce detent wear, and less lateral movement when the selector is installed.

    3. Selector center width of the flat (made wider to accommodate slightly out of spec lowers when Geissele DMR or similar triggers with a wide trigger "tail" are in use)

    4. Selector center flat diameter (made thinner to better accommodate aftermarket triggers)

    We don't call our specs "better than milspec", these are specs born of necessity and practicality. Being modular on both sides, ours are not "in spec" already anyway, as no milspec I know of specified that
    Roger Wang
    Forward Controls Design
    Simplicity is the sign of truth

  3. #13
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    Quote Originally Posted by Lockup1109 View Post
    Thats a good read but it doesnt answer my question. The only people with access to the TDP are colt, FN, the US army and now aparently remigton. I want to know how other companies can get the basic info to build a rifle pretty close to spec. Or is it Reverse Engineering at work?
    The point is: the TDP is out there. If a manufacturer really wants to know the contents, well, a lot of it is pretty readily available.
    Full disclosure: I'm the editor of Calibre Magazine, which is Canada's gun magazine. In the past I've done consulting work for different manufacturers and OEM suppliers, but not currently. M4C's disclosure policy doesn't seem to cover me but we do have advertisers, although I don't handle that side of things and in general I do not know who is paying us at any given time.

  4. #14
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    In our experience, the most important part of the TDP is the tolerances. Without it, we'd have to take measurements from many samples, made by different manufacturers who may (and may not) adhere to the TDP, the result then would be just as inconclusive, and potentially misleading.

    Again using our research as an example, the receiver milspec thickness is .880 +.015 -.002, or .878 to .895. The measurement we took ranged from 0.870 to 0.910, both of the extremes are out of specs, which would result in excessive gaps between the lever and the receiver for the thin receiver, and potential lever binding on the thick receiver. I know of receivers that are thicker than 0.910.

    Old M16 receivers are way thinner than that, 0.74 and 0.84, thinner than that at times.
    Roger Wang
    Forward Controls Design
    Simplicity is the sign of truth

  5. #15
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    Thanks for all the info. Its always made me wonder where these companies were getting their specs from. I wish there was a public copy floating around of even an outdated TDP for the M4. Be interesting to read it.

  6. #16
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    Quote Originally Posted by misanthropist View Post
    Keep in mind Colt is the only one who can make civilian rifles usin the TDP. Colt is the sole source owner of the TDP until 2050, what the Army can do is license it out to people like FN and Remington and give them the ability to make rifles solely for the military. I also have heard that Colt will make changes as they find new ways to make things better for the M4, things that may or may not be seen in other companies rifles.

    If they used the TDP for civilian rifles lawyers would be involved.
    Last edited by sinlessorrow; 10-02-12 at 18:57.
    Quote Originally Posted by C4IGrant View Post
    Colt builds War Horses, not show ponies.
    Quote Originally Posted by Iraqgunz View Post
    This is 2012. The world is going to end this December and people are still trying to debate the merits of piece of shit, cost cutting crap AR's. Really?

  7. #17
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    Quote Originally Posted by sinlessorrow View Post
    Keep in mind Colt is the only one who can make civilian rifles usin the TDP.
    Still not mil-spec.

    Quote Originally Posted by sinlessorrow View Post
    If they used the TDP for civilian rifles lawyers would be involved.
    Especially if the rifles were FA.

  8. #18
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    Quote Originally Posted by Gun View Post
    Still not mil-spec.



    Especially if the rifles were FA.
    I think you missed the point.

    Colt 6921's will be as close as possible, they are the ones who can use all the true specs and techniques.

    Lawyers would be involved because they would be breaching their agreement of their contract when using the TDP to build rifles for the military.
    Quote Originally Posted by C4IGrant View Post
    Colt builds War Horses, not show ponies.
    Quote Originally Posted by Iraqgunz View Post
    This is 2012. The world is going to end this December and people are still trying to debate the merits of piece of shit, cost cutting crap AR's. Really?

  9. #19
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    Not sure if this has been said or not...

    First off, MilSpec and TDP are not the same thing - While the TDP references MilSpecs frequently, those Military Specifications stand on their own and are largely available to any one.

    Think of the MilSpec as ingredients, and the TDP is sort of a recipe, it says to get this MilSpec steel and then machine it to these (CONFIDENTIAL) dimensions, then heat treat using this MilSpec, finish to this MilSpec and plate to this MilSpec.

    Second, parts of the TDP can be released to sub-contractors (there are a butt load of them) to make a part for the company holding the contract. These subcontractors can (usually) sell these parts, and will often openly say that they are made to the same specs as the contract parts that they make... the only snag would be trying to get a Certificate of Conformity from them that says the part complies to the TDP.

    Third, a disturbingly large percentage of people will gladly tell you whatever you want to hear, in order to sell you something.

    1. Trust the well known names you see here.
    2. You may not get what you pay for, but you will never get more than you pay for.
    3. The OP's question was an excellent question.
    Please let me know if I have offended you...
    I would like to move on to my next task.


    I provide legal consultation and training - specializing in the Law of Gravity.

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