Still, a number of things could go wrong from a fuse malfunctioning, a problem with the barrel's assembly to a round prematurely detonating inside the tube, he said.

NPR: Mortar Explosion In Nev. Kills 7 NC Unit Marines

The adjudicator's ruling shows that the assembly was criticised for suggesting that the architects had got their figures wrong.

BBC: Assembly recall urged over HQ row