Bolt-action weapons allow for the elimination of variables to study pure sound signature suppression phenomena. Other than sound transmission through the weapon system itself, there is one primary source of overpressure to atmosphere. Reciprocating (automatic) weapons introduce additional sources of overpressure to atmosphere, namely from their breach during function, which is necessary for ejection. Since the introduction of automatic rifle signatures into the Standard in Public Research Supplement 6.51and Public Research Supplement 6.127, and automatic subgun signatures in Public Research Supplement 6.85, additional weapon system variables have been introduced that influence the blast overpressure and sound fields, as mapped by the measured muzzle and at-ear signatures. These fields continue to be incorporated into the database of suppressed small arm weapon system performance, summarized in Section 7 of the Standard.  Hazard Map Briefs are now presented in Section 8 of the Standard to give users a visual spatial depiction of small arm personnel hazards. The purpose of this Public Research Supplement is to present a first-look at muzzle blast phenomenology for a new addition to the published host weapon systems in the Standard; the 14.5-in KAC SR-25 CC automatic rifle chambered in 7.62x51mm NATO.