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View Full Version : THE TDP and how its possible to follow without access.


Lockup1109
10-02-12, 13:03
Question,
How can the different manufacturers follow adherance to the TDP if only Colt has access to it? How did Rob S make the chart without accessing the TDP? And how do we know the tolerances/testing specs/material specs without actually seeing the TDP? How can any manufacturers claim to meet milspec manufacturing/testing specifications? Just trying to find out how everyone knows the basic TDP specs.
Im genuosly curious.
Thanks
Lockup1109
10-02-12, 13:06
Is BCM/LMT/Noveske/DD reverse engineering actual military issued M4/M16's? I just want to know how the indistry got the specs of "the chart"
misanthropist
10-02-12, 13:09
http://www.defenseindustrydaily.com/Colt-M4-Data-Rights-The-Individual-Carbine-Competition-06942/
Lockup1109
10-02-12, 13:24
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?
nineteenkilo
10-02-12, 13:52
I feel like a fair amount of reverse engineering takes place in the firearm industry, but the technical details can be acquired by any company willing to enter the bid process item for 'this or that' items requiring access. A good for instance is the release of the TDP for the creation of the SOPMOD accessories/BFA's that created such a firestorm back in 96.

As to whether Rob and others have access - I would say no. Colt has spent years in dealing with this sort of issue (rightfully so since they have a substantial investment in R and D). The only leaks that I am aware of have been a result of the Gov and the ensuing NDA's were fairly brutal. Even FN couldn't dodge them completely.

I believe Grant and a few others can offer more substantial insight than I can due to their ongoing business relationships.
NickB
10-02-12, 13:57
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?

Most companies who make claims about being "milspec" are only referring to a particular material type, finish/coating, or reverse engineered physical dimension. For example, a company who advertises a "milspec" barrel is likely referring only to specific attributes such as the steel alloy, twist rate, bore coating, etc., and is not implying that the entire barrel is manufactured to exact TDP specifications. In my opinion, the term "milspec" is incredibly overused (and misused) to the point where it has almost lost its significance.

That said, the rumor is that copies of the official M4/M16 TDP have been leaked throughout our industry, so it is quite possible that some manufactures are producing weapons in accordance with that data.
C4IGrant
10-02-12, 13:57
Question,
How can the different manufacturers follow adherance to the TDP if only Colt has access to it? How did Rob S make the chart without accessing the TDP? And how do we know the tolerances/testing specs/material specs without actually seeing the TDP? How can any manufacturers claim to meet milspec manufacturing/testing specifications? Just trying to find out how everyone knows the basic TDP specs.
Im genuosly curious.
Thanks

Good question. The answer is that there are a lot of older, black market copies floating around. A lot of reverse engineering goes on as well.

The thing that I find most interesting about the TDP is that there are things in there that Colt deviates from as they found a better way to do it.

The TDP is a living/breathing document. So if you got a look at one 5 years ago, things have changed.



C4
C4IGrant
10-02-12, 14:02
Most companies who make claims about being "milspec" are only referring to a particular material type, finish/coating, or reverse engineered physical dimension. For example, a company who advertises a "milspec" barrel is likely referring only to specific attributes such as the steel alloy, twist rate, bore coating, etc., and is not implying that the entire barrel is manufactured to exact TDP specifications. In my opinion, the term "milspec" is incredibly overused (and misused) to the point where it has almost lost its significance.

That said, the rumor is that copies of the official M4/M16 TDP have been leaked throughout our industry, so it is quite possible that some manufactures are producing weapons in accordance with that data.

Right on. To dumb it down even further, many companies use the term "mil-spec" to mean that their parts will fit/work with an actual M16/M4.

An example of this is the Receiver Extension. Many companies offer/make a "mil-spec" one. In this term they mean that the SIZE of the RE conforms to the military standard (not the quality and how it is made).

The TDP calls for the RE to be hammer extruded and made out of 7075T6. To my knowledge only Colt and BCM offer this (could be others, but those are the only two I know for a fact that follow this).



C4
Split66
10-02-12, 14:05
Because they dont adhere to the TDP. Some materials/specs/testing procedures are well proliferated and have become an industry standard. Other bits, companies like DD and BCM use their own specs ( gas port size, gas system length, lower specs etc.)



Its that easy.


ETA google MIL-C71186, its an older outline defining some of the basics and testing protocol, no specifics as per material or drawings in the PDF but a fascinating read non the less.
Doc Safari
10-02-12, 14:06
I've heard the one about a manufacturer seeing an older version before.

In a nutshell, Colt would have the latest information, but XYZ company has a version from several years ago.

I'm thinking this isn't necessarily that big a deal: sometimes changes are miniscule, or make manufacturing easier (or cheaper) and don't necessarily mean your carbine is inadequate because it wasn't made with Change #173.
Gun
10-02-12, 14:31
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.
Duffy
10-02-12, 14:44
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 :p
misanthropist
10-02-12, 14:45
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.
Duffy
10-02-12, 14:52
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.
Lockup1109
10-02-12, 15:23
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.
sinlessorrow
10-02-12, 17:51
http://www.defenseindustrydaily.com/Colt-M4-Data-Rights-The-Individual-Carbine-Competition-06942/

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.
Gun
10-02-12, 18:17
Keep in mind Colt is the only one who can make civilian rifles usin the TDP.

Still not mil-spec.


If they used the TDP for civilian rifles lawyers would be involved.

Especially if the rifles were FA.
sinlessorrow
10-02-12, 19:22
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.
K.L. Davis
10-03-12, 23:41
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.