Quoted: Mil-spec is bullshit.  It is something that the internet is obsessed with.

Thankyou, your rant beats out my rant, which allows me to sit here and smile.  Now I can go back to looking for pictures to post, or something else that won't get me irrate....

Quoted: lol....  OK, I got it now. be on the lookout for more newbie Q's as I am on a mission to build an AR for very cheap, hence buying some items used, etc... and need to know what I'm looking at sometimes. thus far I have a lpk on the way, and a lower to be picked up at the local.

Hit the build forum and start reading, there are a lot of posts from people who are getting started in building.

This is something I posted a few months back.  It seems somewhat applicable to this discussion:

What is Mil Spec ?
What does that term mean to you ?

It is an overused term in this industry (and at times, I have been as guilty as anyone).
I think the term and its' honest definition has evolved over time.

In order to understand how it is used today, I think we need to take a look back at the civilian/commercial AR industry in its' relative infancy. In the days where there was only Colt and a bunch of low budget copies.
If we look back about 15-20 years ago, the quality of the average parts offered on the market was significantly less than what we choose from today. If you picked up a parts kit or complete rifle, chances are your set up included such products like:
-Cast front sights instead of forged
-Roll pins used instead of steel dowels to pin a front sight
-Sling swivels with no rubber sleeve
-Washers for flash hiders that came straight from a hardware store
-Plastic handguards with no heat shield or if they had them – plastic
-Plastic delta ring
-Receivers that an inferior plating (Not HC anodized)
-Cast lowers and uppers instead of forged
-Chrome moly was presented as chrome lined
-Lower parts that were probably reject scrap M16 parts that were sloppily cut and reparked
-A buffer and spring not fit for an airsoft rifle

Then as the market grew, so did competition. Competition spurred strategies such as “our parts are better than your parts because of . . . “. Which led to a slow influx in higher quality parts and rifles. In many ways (as I remember it) Bushmaster (aka Quality Parts Inc.) led this charge with a article in Spring 1992 Soldier of Fortunes “Fighting Firearms”, titled Bushmaster Builds a Better M16. At the time Bushmaster was the only major company making a rifle with a chrome lined bore, correct trigger and takedown pins, and a bayonet lug.

As the market and competition grew, the term Mil-Spec became one of the most popular descriptions in the industry. It was a term used to define a difference between some lower quality materials and some of the new higher quality materials.
Its my opinion that an honest use of the term "Mil-Spec" in that context was to say, our delta rings are not plastic but are made of aluminum – just like the military version.
Or our front sights are not cast, but forged like the M16 would have. In that, it described the use of materials and manufacturing that are generally consistent with the military issued version.

Well with the current continuing growth of the AR industry coupled with the powerful tool of the internet, information (and sometimes mis-information) can be disseminated at a rate never before imagined. With this, terms and expectations have changed dramatically to the sophisticated consumer.

So what does Mil-Spec mean today ?
My $.02  . . . . In its most technical and literal sense it means as defined by the TDP. As I understand it the TDP would be all of the manufacturing dimensions, material and manufacturing specifications, quality control testing, and tolerances (+/-) as set forth by Colt for the production of the parts and complete rifles as delivered to the US Military. This information is owned by Colt and is very purposely not released for public consumption. (FN now leases this info for the US M16 rifles it produces) Which really means that by a strict literal definition virtually none of us really know what the true 100% Mil-Spec is. Or you could say there are a very small handful of people in the world that do – and they ain’t talking. Although I do like the Colt product, the above paragraph should not be taken as an advertisement for civilian Colt. Because I personally am not convinced that true 100% Mil-Spec QC is anything civilians or LE will get from a store bought AR15.  (I just dunno?)  My personal belief is that a true 100% Mil-Spec carbine can only be acquired (indirectly) through your local military recruiters office. (i.e. – enlistment or re-enlistment). But that debate is perhaps a different topic?

The Colt TDP is to say that every other AR has been reverse engineered. Which really does not directly translate into a bad thing. Current manufacturing, measuring, digitizing, CMM, etc techniques reproduce an identical product if given a broad sample of product to work with. There are thousands and thousands of private security, law enforcement, and other non-military personal that are fighting for their lives and our freedoms with a DPMS, Bushmaster, Rock River or Armalite rifles – all over the world, and they are doing quite well with it.

So back to the topic at hand – the contemporary definition of Mil-Spec. If the sophisticated consumer defined true 100% Mil-Spec as the TDP, and none of us consumers will have the TDP and therefore can not confirm that a product complies to the TDP, then the term can only be used in reference to a military context discussion about an issued rifle.

I feel the honest contemporary definition of Mil-Spec in the context in which we use it would be “Mil-Spec” is short for “Mil-Spec feature”.
Some examples:
To describe a Mil-Spec trigger pin or take down pins, is to say they are the standardized and not the oversized type.
To describe a Mil-Spec front sight, is to say that it is forged and a taller “F” to be barreled to a flattop and the shorter to be barreled to an A2 upper.
To describe a Mil-Spec M4 profile barrel, is to say that it is 4150, chrome lined, and 1/7 twist. Or even to say regarding chrome moly/chrome lined vs. chrome moly, where chrome lining is Mil-Spec.
To describe a Mil-Spec stock, is to say that the dimensions are compatible with Colt stocks as opposed to the large OD of various commercial units.

It is my opinion that this is the current definition of the term Mil-Spec (Mil-Spec = Mil-Spec feature).

Your thoughts ?

Yeehawww Paul.

That about sums it up.

Denny