Additional examples of the use of infrared fiber optics to probe the decomposition processes in burning gun propellant strands are presented. These experiments involve measuring the absorption across an open gap between two embedded fibers as it fills with gaseous decomposition products. Several improvements have been made to the experimental technique. In the most significant, detection techniques for the nitrogen oxide species NO2 and NO have been added to the N2O detection system developed in earlier work. NO2 detection was accomplished by differential absorption of red and green HeNe lasers, while NO detection used a tunable infrared diode laser. We have observed N2O, NO2, and NO evolving into the observation volume during the burning of an RDX-based composite propellant. Our observations indicate that NO appears at similar times as N2O, that is, while the observation region is relatively cool and far from the burning surface, while NO2 can significantly precede both NO and N2O.