Double D., That's a good idea about the hard hats, thanks, An errant bolt could go way, way up and then come almost straight down. If 4 feet of fuse is good for 300 yards of walking, then 3 feet will easily cover walking back to 60 or 70 yards.
Good advice, Flagman, also very good advice for placement of your powder box behind your gun's position on the firing line. Our powder box was 25 feet behind our cannon and 15 feet to the left of it when a whole roll of fuse burned up in a shower of sparks which blew over Mike's head directly to the rear. Good thing the powder box cover was closed and the box was on a diagonal!
KABAR2, No need for getaway quads or complex rocketry ignition gear. Really, and I mean this, WE NEVER RUN!! We simply use enough fuse of a known speed so we can light it turn around, walk the required distance to cover, get behind it, count to 20 and BLAM. Mike and I have done many of the type of carefully crafted experiments where cover is not absolutely necessary, but a common sense, extra precaution which we take advantage of.
Victor, You are still incorrigible, simply incorrigible!
Mike Scott, Please see what KABAR2 wrote. Everything you asked about is explained in a logical and forthright manner. Thanks Allen, we could not have said it better!
We sure are getting excited now, not only did we find enough Honduras Mahogany to build all of the Chassis structures we have to make for our last Seacoast Artillery piece in our Magnificent Seacoast Gun Series, but we also bought three sheets of 18mm Baltic Birch for the Petard VS Medieval Doors experiment. The Upper carriage for the 150 Pdr. Armstrong Gun M1864 was made of Rosewood. We picked up enough to do 6 carriages from a Canadian importer 8 years ago and it has been stable every since. The Baltic Birch will make a VERY strong set of doors and should hold all of it's steel and iron hardware which will be bolted and riveted just like the ancient ones. What we need now is a good door design to duplicate. The following are a few of the many photos of old castle and fortress doors we have looked at.
Tracy
An attractive woman to be sure, but those doors are a bit large, don't you think?

There's a timber locking bar, but those door hinges are too gaudy for us.

Old, riveted, reinforced with iron cross bars, but not a two door design.

A nice double door design, but a little fancy for us, I'm afraid. Looks like a Church door.

Whoa!! Hold the phone, that's a design any axeman would hate to see before him. Quite a "stand-off" there, but with a big enough petard, we believe that this door could be defeated. It would be difficult to withdraw your tree-trunk battering ram from this one!

Ah, we think this one is just right! Maybe one-half the rivets would do the job? Maybe a mid height wrought iron bar to anchor the timber locking bar brackets with bolts.
