buickid
Enlightened
I think the concern was that the ammo can will pressurize the blast, and the can will burst open, spewing forth firey flames of fire and possibly burning/red hot debris, instead of venting. Kind of like how gunpowder will burn if drawn out in a line, but explodes when compacted. In an earlier post, even an ammo can with a 6" hole cut in the side blew apart when the cells went off.