TriggerTech AR triggers are designed to accommodate a wide range of tolerances; however, AR safety selectors do not follow a universal standard. Short-throw safety selectors, in particular, require tighter tolerances between the safety and trigger to function properly.
In early 2017, we updated our design tolerances to improve compatibility with most short-throw safety selectors. That said, some short-throw selectors specifically designed for mil-spec (housing-less) triggers may not be compatible with TriggerTech triggers.