TDP and reverse engineering

[paradoc]

Since the TDP contains the magic specs that make a "tier 1" gun, why have the other manufacturers just not reverse engineered them by examining weapons that are built to spec?

A lot of other industries reverse engineer things so why not the AR 15?

[Don Robison]

Since the TDP contains the magic specs that make a "tier 1" gun, why have the other manufacturers just not reverse engineered them by examining weapons that are built to spec?

A lot of other industries reverse engineer things so why not the AR 15?


Why bother when they can build something with a wider profit margin that "looks" the same to the casual buyer.

[couch_potato]

What the heck is a TDP?

[paradoc]

TDP- technical data package, the technical specifications for the government issued M16/M4 family of weapons. Colt and the US Gov't guard it religiously and it is only shared with contracted companies , ie FN who makes gov't m16s as well.

Companies that receive it sign an agreement not to use the information for commercial purposes and not disclose the contents of it as well.

[Jay Cunningham]

Since the TDP contains the magic specs that make a "tier 1" gun, why have the other manufacturers just not reverse engineered them by examining weapons that are built to spec?

A lot of other industries reverse engineer things so why not the AR 15?

We have SME's here who know more than I do and will likely chime in, but the short answer is THEY HAVE. It's just that you don't get a mil-spec gun when you reverse engineer, you get a copy of a mil-spec gun.

[NickB]

What the heck is a TDP?


A Technical Data Package is a technical description of an item adequate for supporting an acquisition strategy, production, engineering, and logistics support. The description defines the required design configuration and procedures required to ensure adequacy of item performance. It consists of all applicable technical data such as drawings and associated lists, specifications, standards, performance requirements, quality assurance provisions, and packaging details.

A TDP in this thread refers to that package for the M16, but TDPs are created for most (all?) milspec items. This differs from Commercial Off The Shelf (COTS) which are manufactured to commercial specs. Under Clinton and William Perry's Department of Defense, "milspecs" were slated for re-evaluation, elimination, and replacement with commercial standards and performance specifications. Before Perry if the DoD wanted to buy COTS, they had to fill out a waiver and get approval. One of the first things Perry did after taking office was issue a memo (now infamous in the DoD) stating that in order to purchase anything with a milspec you had to get a waiver, but COTS was now automatically approved.

For some things the elimination of milspecs makes sense:
1. Semiconductors (computers/electronics in general). The government would write milspec requirements for computers when in reality the government doesn't know the first thing about semiconductors compared to Intel, IBM, etc. The result was a bidding process that took months or years, incredible cost (time/money), and a product that was inferior to what they could have purchased for $500 in 10 minutes from www.dell.com.

2. Little things - pens, computer paper, a clamp to fix a leaky steam pipe, etc. There is no reason to write a TDP for ash trays (yes, it does exist, and it's incredible), or require some maintenance guy in Denver to order a clamp through acquisition in Washington, who then waits until they need sufficient quantity to solicit vendors for a good price, go through the bidding process, obtain the part, then ship it to Denver. Why doesn't he just drive to Home Depot, use a government credit card to buy the $5 part, and save the $1000 in gas that has leaked from the pipe while he was waiting for the part to arrive from Washington?

3. Once a TDP is established, it is often hard to change. As it pertains to AR15/M16 rifles, consider things like MPI (magnetic particle inspection). MPI is 50+ years old - the concept has been used in primitive forms for over a century. There are more advanced ways to find flaws in the metal (their merit is a discussion for another thread), but we still MPI test. Why? It's in the TDP. Even if Colt had a magic wand that would accomplish the same thing for less money, in less time, we would still use MPI because it's in the TDP.

On the opposite side of the coin, the elimination of milspecs and TDPs has created significant problems, primarily in industries where COTS items do not exist, or where commercial equivalents to milspec standards have not been determined. Furthermore, my understanding is that the TDP only states the requirement, not the reason that requirement was chosen. Why was 7075 aluminum chosen as the milspec material for lower receivers? I assume it has something to do with durability, cost, weight, availability, ease of manufacture, etc., but the guys who chose it are probably a) retired, or b) unknown, or c) dead.

So to answer the OP's question about why no one has reverse engineered the TDP, I think it's a combination of things: 1) some manufacturers have, or at least come damn close, often meeting or exceeding the quality and performance of milspec guns; 2) the TDP isn't always the best solution - it's just the solution we have deemed acceptable through decades of trial and error; and 3) donr is right when he says the average Joe consumer doesn't know/care enough to spend milspec money on a gun he's using to punch paper at the range.

Like all industries, the firearms market is driven by supply and demand - cracking the TDP isn't like breaking into Ft. Knox. If consumers demand quality on par with the TDP, we will have it. If consumers demand quality superior to the TDP, we will have it. If consumers continue to demand made in China-quality crap, we will continue to have that too. Regardless, we would all do well to find some sort of middle ground between milspec and not. The TDP is a safe way to manufacture a rifle, but that doesn't mean it's the best. I'm sick of people worshiping anything that's 7075, Type III Class I, shot-peened, MPI tested, MP proofed, blah, blah, blah. Material names and manufacturing processes don't mean anything - if you can make a gun out of balsa wood and Bubblicious that will out-perform a Colt, I'll buy a dozen. Rifles produced in accordance with the TDP are a good baseline for performance, but nothing more. Most of us on this forum have spent thousands of dollars on non-milspec upgrades to our weapons - what does that tell us? Maybe it's time we start demanding more for our money...sometimes I can't help but feel like Kevin Bacon in Animal House when I buy new gear: http://www.youtube.com/watch?v=gKpKSZGSkuo

[Army Chief]

Nick pretty much nailed this one, and I would have to concur when he points out that a rather inflexible government TDP may not even always be the best solution; that said, in most cases this comes down not to an inability to meet the standard, but rather an unwillingness to assume the greater costs involved in rigorous component testing, inspection and quality control.

Most of the better-known AR vendors could build a TDP-compliant weapon with little difficulty, but at what price point? If the end state for the consumer market is that Bushmaster, Stag and the rest are having to charge the same price of admission that Colt charges, then what incentive is there for the average buyer to buy something other than the Hartford original? My purpose here is not to re-ignite the old flame wars of one manufacturer versus another, but if you're not looking at the economics behind the question, then you're probably missing the point.

As has been stated, most civilian buyers neither need, nor are willing to pay for, a true hard-use, battle-proven, fully TDP-complaint carbine. They want something that looks close, shoots well enough, and is compatible with all of the accessories that are out there. Now, if that is the sweet spot in the non-military market, and you're a private company building primarily non-contract weapons, wouldn't it make sense to build according to those loose perameters with an eye on the bottom line? Of course it would, and the market reflects that.

The companies that we tend to hold in high regard around here are building according to a different formula for a different customer, and in that sense, they are the "real deal" where others may fall short. Here, as elsewhere, you can look at price points and pretty much get a decent idea as to how MILSPEC your weapon truly is. Again, it isn't the MILSPEC itself that even matters in many cases, but there is no substitute for quality components and competent assembly, and those things cost more to deliver.

Want to know why your pet third-party carbine isn't TDP compliant, gents? In the overwhelming majority of cases, you really need look no farther than the price tag. Money drives the train.

Chief

[CarlosDJackal]

An item that is manufactured to specs but is not run through any type of QC is still a piece of crap. Even Tier 1 manufacturers will produce crap. The difference is they try to catch these with multiple Quality Control checks.

[militarymoron]

It's just that you don't get a mil-spec gun when you reverse engineer, you get a copy of a mil-spec gun.
yup - that's the problem with reverse engineering - you end up with measurements of a mil-spec gun but still don't know the 'real' spec. a mil-spec gun should be manufactured to the tolerances held in the TDP. say the tolerance is +/- .005" (for example), the measurement can vary by .010" but still be in spec. you'd have to measure a large sampling from different manufactured batches (since they can vary and go from one side of the tolerance to another) to narrow it down and guess at the nominal. because of this uncertainty, you might have to make your reverse-engineered parts to a tighter than TDP tolerance to ensure that they interchange, as you have your own manufacturing tolerance stacked on top of your uncertainty. that's why we sometimes see too-tight magwells, or problems with front-rear takedown pin distances.

[Gramps]

Thanks guys, that pretty much puts it in BLACK and WHITE for this old man.

IE: Makes sense to me. (But my sense could now be +/- .025);)

[paradoc]

Thanks for the information, some of which more than answered my original question with actual thought. That's why I asked it here rather than TOS.

[Army Chief]

I think I got a bit confused when we started down the "reverse-engineering" path. Granted, that is an imprecise means of duplicating a weapon produced to a particular standard, but is the sidebar implication here that the TDP itself is some kind of semi-classified, close-hold document?

I was under the impression that any individual or firm that wished to see the MILSPEC standard defined in the TDP could gain ready access to the original information, which would make the whole reverse-engineering question rather moot. Not so? It's been my experience that when the government publishes an equipment/contract standard for something like a small arms system, there isn't a great deal of secrecy involved. Anyone can see what the requirements are, but obviously not everyone can tool up to meet them as part of submitting a competitive bid.

Are we now suggesting that the actual TDP standards are unknowable or unobtainable to non-contract holders?

Chief

[RAM Engineer]

It depends on who OWNs the TDP. (I don't know, but I'm sure someone will be along shortly to tell us who does).

If a company develops something for the Army (like a Missile), that company OWNS the TDP, and grants the Govt has rights to it (or part of it). But the Govt can't just go out and give that TDP to a competitor.

Some companies sell the rights to their TDP to the Govt.

Some TDPs are created by the Govt (this used to be more common in ye olden days).

TDP's that are owned BY the Govt, and can be moved from contractor to contractor.

I'm sure there are other iterations, but those are the ones that jump to mind.

[C4IGrant]

I think I got a bit confused when we started down the "reverse-engineering" path. Granted, that is an imprecise means of duplicating a weapon produced to a particular standard, but is the sidebar implication here that the TDP itself is some kind of semi-classified, close-hold document?

I was under the impression that any individual or firm that wished to see the MILSPEC standard defined in the TDP could gain ready access to the original information, which would make the whole reverse-engineering question rather moot. Not so? It's been my experience that when the government publishes an equipment/contract standard for something like a small arms system, there isn't a great deal of secrecy involved. Anyone can see what the requirements are, but obviously not everyone can tool up to meet them as part of submitting a competitive bid.

Are we now suggesting that the actual TDP standards are unknowable or unobtainable to non-contract holders?

Chief


The Govt controls the TDP for small arms. If you are awarded a contract, then you receive it and sign an NDA.

I have to make a point here about companies having or not having the TDP. There are tons of copied TDP's running around the firearms industry. I can pick up the phone and call a half dozen people about what is said in it. Large companies have the ability to see a good portion of what is in this document. If for some reason they do not know how to assemble an AR, they can just go to a Colt armorers class and learn all they need to know.

To prove my point, BCM (which is a very small mom & pop company) have been building uppers to the TDP standard. They did the research on barrel steel, testing, etc and went out and made it happen on a limited budget. So if they can do it, any of the big boys can as well.

What I think people fail to realize is that these companies CHOOSE to not follow the TDP. Why you ask? Because buying the rare and expensive barrel steel is hard, HPT/MP testing bolts with barrels is a gigantic PITA. Just trying to get the "blue pill" to do HPT is a difficult thing. Then you have the cost of training your employees on how to properly assemble a weapon, not to mention training your QC staff.

IMHO, if you want a weapon built by people the "give a chit", you should really look at small companies that build one weapon at a time. Such companies would be Bravo Company, ADCO, GTS, etc. Their attention to detail is going to be much better than a guy that hates his job making $7.50 an hour.


C4

[paradoc]

makes sense, BCM, LMT seem to have a "better than spec" reputation.

[SHIVAN]

militarymoron nailed what I had written out....

[WS6]

The Govt controls the TDP for small arms. If you are awarded a contract, then you receive it and sign an NDA.

I have to make a point here about companies having or not having the TDP. There are tons of copied TDP's running around the firearms industry. I can pick up the phone and call a half dozen people about what is said in it. Large companies have the ability to see a good portion of what is in this document. If for some reason they do not know how to assemble an AR, they can just go to a Colt armorers class and learn all they need to know.

To prove my point, BCM (which is a very small mom & pop company) have been building uppers to the TDP standard. They did the research on barrel steel, testing, etc and went out and made it happen on a limited budget. So if they can do it, any of the big boys can as well.

What I think people fail to realize is that these companies CHOOSE to not follow the TDP. Why you ask? Because buying the rare and expensive barrel steel is hard, HPT/MP testing bolts with barrels is a gigantic PITA. Just trying to get the "blue pill" to do HPT is a difficult thing. Then you have the cost of training your employees on how to properly assemble a weapon, not to mention training your QC staff.

IMHO, if you want a weapon built by people the "give a chit", you should really look at small companies that build one weapon at a time. Such companies would be Bravo Company, ADCO, GTS, etc. Their attention to detail is going to be much better than a guy that hates his job making $7.50 an hour.
C4


From my talks on the phone with SDI that sounds like them as well as far as their civilian sales go. I know I have been waiting for 2 months now for my rifle and I belive they have a very limited amount of very dedicated employees who have been on the job 5-20 years.

As to the TDP, I will have to agree with Nick. Some of it is done "just because", not because of a functional reason.

[davemcdonald]

Don't get all wrapped up with TDP. The TDP that Colt and FN have is for the weapons that they make for the military. Now the Colt rifle that you buy for sport shooting or for law enforcement duty is a great rifle and proven on many occasions but it is not built to the TDP. While some manufacturing processes are the same, if it is not built 100% to the TDP then it is not completely mil-spec. So unless you have a Colt M16, M4 or military variant or a FN M16 then you do not have a rifle built to the TDP and therefore it is not mil-spec. There are better choices out there than mil-spec. Grant gave some good advice with the small shops that want to produce the better weapons. Also ask some of the instructors that are on this site which ones work and which ones don't. You have a vast amount of experience right at your figertips. Remember, everybody makes a lemon every now and then, there have even been some dogs that snuck out of Colt's doors. What ever you decide to get ....get good with it and you will find out soon enough on your own whether your rifle is up to task.

Dave

[C4IGrant]

Don't get all wrapped up with TDP. The TDP that Colt and FN have is for the weapons that they make for the military. Now the Colt rifle that you buy for sport shooting or for law enforcement duty is a great rifle and proven on many occasions but it is not built to the TDP. While some manufacturing processes are the same, if it is not built 100% to the TDP then it is not completely mil-spec. So unless you have a Colt M16, M4 or military variant or a FN M16 then you do not have a rifle built to the TDP and therefore it is not mil-spec. There are better choices out there than mil-spec. Grant gave some good advice with the small shops that want to produce the better weapons. Also ask some of the instructors that are on this site which ones work and which ones don't. You have a vast amount of experience right at your figertips. Remember, everybody makes a lemon every now and then, there have even been some dogs that snuck out of Colt's doors. What ever you decide to get ....get good with it and you will find out soon enough on your own whether your rifle is up to task.

Dave

Dave is right. The only way to get a TRUE Mil-Spec weapon is to enlist. With that said, you are much better off with a company that tries to follow the TDP VS a company that follows no standard.


C4

[Army Chief]

I don't get the impression that most of us are too hung up about a particular MILSPEC or TDP standard, per se, but I do think that we might tend to view a TDP-compliant company like Colt as a safer bet across their other product lines.

I say this simply because it stands to reason that the component testing, inspection and QC details (that so many others skip) are already integrated into their regular production processes. I'd also wager that there probably isn't too much difference quality-wise between what's going into Colt's commercial parts bins and what going into their defense parts bins -- but I could always be mistaken about that. Your point about the smaller operations is, of course, perfectly valid, but when the discussion turns toward volume production, I do think there is still some logic to dealing with a firm that has contract/TDP/MILSPEC experience.

Chief