"Gary" wrote in message
oups.com...
That sounds about right. As a rough rule of thumb, mortar-fired
firework shells go up about 100 feet per inch of diameter. Many
small-to-medium municipal shows don't shoot anything above 6" in
diameter, because larger mortars have to be buried for most of their
lenght, while 6" tubes (or smaller) can be set above ground.

Larger shows will include 8-12" shells, and even larger shells are
available (though they don't see a lot of use).


I helped a guy build some quite large ones few years back, the coolest ones
were the 5lbs of calf's milk and 1lb of flash powder in the center. Man that
powdered milk can burn for a long time. he did the show in Wildrose, ND
"rostins thunder & lightning show" something like that.