Now don’t get me wrong. I am glad they did it. If the AR15 didn’t use milspec specifications then we wouldn’t be able to mix and match parts from all these different manufacturers.
But, since the AR15 was for the civilian market and not ever issued to the military why was it 8manufactured milspec.
Now this is a technical question for someone who knows the history of the AR15’s development.
My theory is since the manufacturers were already set up to produce the m16 then it only made sense to produce a civilian semiautomatic version with basically the same parts.
Is the only difference really the fire control system?
The first civilian AR15 was the Colt SP1, which was essentially a semi automatic M16. M16 is the military designation, and AR15 was the original Armalite designation, AR being their abbreviation for Armalite.
Yes, the only substantive difference between a civilian/LE AR15 and a military M4 is the lower receiver and fire control group. Now that’s Colt, mind you. Obviously you have a plethora of AR variants that are way off the reservation, where virtually nothing is interchangeable.
The original design is pretty much intact, with only a few minor updates. The largest of which was the flat top upper. There are more subtle changes that were made over the years, like the feed ramps being slightly tweaked.
Bottom line is that the AR-15 existed before the military M-16. Colt did not make a civilian version of the M-16; the DoD type-classified the AR-15 as the M-16.
You have to play the name game semantics. The AR15 was never issued to the military. The M16 was. Totally different. Completely. Couldn’t be any more different.
The original AR-15, as designed and built by Armalite was a select-fire weapon, and there for not “a civilian version”.
The later Colt’s Manufacturing examples of "XM16"s were identical to the AR-15 in every way, except for the Marking of “XM16”, and “US Property” markings.
The AR-15 was purchased and issued to “the military”, Malaya bought some, the US Army bought some for testing, and a number (1000 to be exact) were given the Republic of Vietnam for issue to their troops and US Advisors.
The semi-automatic version of the “AR-15” came about after the events of item #3, so the “civilian version” post-dates the “military version”.
If you want to play at semantics, there is technically no such thing as “milspec”. There is the technical data package or TDP, which describes in intimate detail the specifications of each model of firearm accepted by the government. It is a huge amount of information covering dimensions, procedures, materials, tolerances,… ad infinitum.
In terms of civilian AR-15s, none of them meet the TDP 100%. If they did they would be select fire M-16s, or M-4s. When something is said to be “milspec” that means it is built as close as possible to the TDP. Many parts of an AR can be 100% compliant with the TDP. Some cannot, like the FCG, but can be manufactured as closely as possible to that standard. That is really all that is important. If an AR is built as closely as possible to the TDP, then one can have a degree of confidence in the construction of that AR. Your would expect certain criteria to be met.
That does not mean that TDP is the only measure of quality, let alone the pinnacle of perfection. A KAC SR-15 deviates from the TDP in a number of areas. I would not say that makes it “substandard”. Though as a general rule, most deviation from TDP is not for the better.
Deviation from TDP can be good or bad, and TDP rifles certainly do go down. All it does is provide a standard reference to compare against.
All rifles, carbines, and parts made in accordance with these specifications are “mil-spec”. There can be “mil-spec” parts sold on the civilian market, if they are made in strict accordance with the military/Colt drawings, and tested in accordance with the applicable specification. However, since the drawings are proprietary to Colt’s, and the military drawing can only be used for Government contracts, the only (legal) civilian source for “mil-spec” parts would be Colt’s or a Colt’s licensed producer. I mean, how else could you get access to Colt’s proprietary drawings?
There is not a universal size for commercial parts, each vendor would build to there own specs and commercial parts do not interchange. Now when a manufacturer builds mil spec parts with little variance between them, you will have a nice tight build. This is why when building a precision rifle you would want matched upper / lower and a matched barrel from a manufacturers that has great QC.
This is why there is a difference when building a rifle with parts from geissele vs parts from Anderson even when it’s just the receivers.