This ammunition is being fired off to give an audible message meaning, "Warning! I am pointing a gun at you, please duck". So, why not skip the ammunition and go straight to the audible message?
Let's suppose we mount a pair of speakers on the rail of the C7, in forward-facing tubes, playing irritating tones of slightly different frequencies. When the barrel is pointing towards you with the speakers playing, you'd hear a really loud beat frequency, rattling like a machine gun. As the barrel swings away to either side, the noise would drop off rapidly. With a few seconds of observation, people would learn to hear when they are being targeted, and would duck accordingly.
So, instead of suppressing fire, the first step would be to click on the speakers and point weapons at the opponents. Actual ammunition would only be fired if the opponents did not duck. The Canadian Forces would save ammunition, and civilians would have fewer stray projectiles punching through the walls of their houses. Fewer opponents would be shot, but shooting opponents isn't the primary goal of suppressing fire anyway.