EmericD said:

M855 from a M4; 400 m range (ICAO atmosphere); residual velocity 533 m/s; 151.8 dB (0.777 kPa) at a near miss distance of 1 m.

7.62x39 mm PS from an AK; 400 m range (ICAO atmosphere); residual velocity 400 m/s; 153.7 dB (0.967 kPa) at a near miss distance of 1 m.

DM41 from a 20" SCAR-H; 400 m range (ICAO atmosphere); residual velocity 554 m/s; 154.5 dB (1.060 kPa) at a near miss distance of 1 m.

Thank you.  Those numbers seem to roughly correlate to the "500 m" results (actual distance was 450 yds -- a shade over 400 m -- according to Garand Thumb), so perhaps the video test was not so bad.