Rocklock1, I do remember the 400 yard rock and the 'special' shot at it, but what I recall most vividly was what changed our minds about the way we were igniting the 4" mortar. Before I hauled that beast out to Denver, we used standard green fuse to fire it. Nobody liked waiting for 5" of that stuff to burn down to the powder, so i looked around and found that some folks were using what they called 'quills' back in the mid 70s, but 'quills' then, were not the same as 'quills' are today. Back then we were filling the whole paper soda straw up with 3Fg BP with an inch of black match taped to the tip. It burned rapidly for one full second, like a huge flare, before the Ka-Boom.
So back to the 400 yard rock at Tunnel No. 1, Route 6 canyon just west of Golden, Colorado; we used the powder-filled straws and broke 3 or 4 trying to stuff them down the dirty vent, because we forgot the .22 cal. vent brush. Quite a little pile of powder accumulated on the ground under the mortar's breech end.
It was Mike's turn to bombard the big rock at 400 yards, so he lit that little piece of black match with someone's Zippo and immediately disappeared in a cloud of powder smoke! As he staggered backward, the mortar went off, Ka-Blam!!, adding to the confusion! Everyone knew what happened, so why did not one of us remove the spilled powder BEFORE this happened? It's a mystery to this day, but at least we were smart enough to switch to using 5 inches of black match, which, in the vent, burned much quicker to light off the mortar from then until we changed to 'sticky, quick match quills' in 2009.
Mike and Tracy