Maybe ATK got it wrong? http://www.dtic.mil/ndia/2009infantr...ioniii8524.pdf
On page 7 there are two photographs, one of the flame from a Fed GMM primer and one from a different primer with the caption, overflame caused by PETN.
Wouldn't be the first time someone got a compound wrong in a briefing. I can see someone saying DDPN and someone else typing PETN.