Retired Infantry. Saw two perfectly good M16A2s blown in half during training at NTC FT Irwin CA during Desert Shield live fire exercise (M1s, BFVs, Infantry, Combat Engineers, the whole Heavy BCT) clearing simulated Iraqi trenches on same day - no one hurt. High adventure with tank rounds and 25mm blowing entry points and Infantry pouring into trenches to clear. Extremely dusty, sandy, dirty conditions. My hypothesis - M16A2s got dirty/dusty and jammed. When Soldiers stripped the live rounds out the projectile stayed in the lands and the brass came out. Used forward assist and muscle to drive fresh round in and .....