AR-15 Reliability Test Cases
Below are some common AR-15 archetypes with explanations of the factors affecting their reliability. The original M16, with a 20" barrel and 12.5" gas system, is generally regarded as the coolest-running, softest-shooting, and most reliable AR-15 archetype, and is used as the baseline against which other archetypes are judged in the below charts. See if you can spot an archetype that is similar to your AR-15 (or one you would like to build), and get a sense of the problems that may be inherent in its design so that you can address those concerns correctly. For a detailed breakdown of the many factors impacting AR-15 reliability, see the companion article: AR-15 Reliability; an in-depth look.