When talking AR-15’s, the term ‘mil-spec’ gets thrown around a lot, but what is a ‘military specification’ and what exactly does it mean?

Mil-spec is the MINIMUM requirement as set by the United States Military. The Military Specification for the M16/M4/AR15 rifle talks not only about SIZE of parts, but METALS used, as well as metal TREATMENTS and HOW the rifle is ASSEMBLED.

The ‘mil-spec’ is an example of what is called a ‘TDP’ or Technical Data Package. Here’s a formal definition:

Technical Data Package – “A technical description that is adequate to support acquisition of an item, including engineering and production, the description consisting of all applicable technical data such as engineering drawings, associated lists, product and process specifications and standards, performance requirements, quality assurance provisions, and packaging details. Acronym: TDP”

Colt Defense still owns the TDP for the military service rifles. The Colt TDP is heavily controlled and contracted out to FN (and soon Remington as they begin making some military M4’s).

Quite simply a rifle that is built to mil-spec is a better rifle than one that is not. Mil-spec refers to much more than just a blueprint showing part sizes and an assembly diagram. AR-15’s are sophisticated weapons from an engineering standpoint and there IS a difference between the bargain rifle and a higher end gun. If you choose wisely you can pick a rifle in your budget with features you want and the quality you deserve.

If you are interested in a long read, here is the full TDP: http://www.everyspec.com/MIL-SPECS/MIL-SPECS-MIL-C/download.php?spec=MIL-C-70599.025760.pdf