Capt William, ye ask two, I'll answer two. Range was 200 yards, an' the shoot was paid for by Greystone Productions for the History Channel (Weapons of the Alamo was the working title, planned to air in December). Yah, different time, different place, but valuable lessons on how picky the aim is and how far the steel will fly.... USFAA is an organization for US Army artillerymen, HQ is Fort Sill OK, and the Loyal Train Chapter is for reenactors... so I got some serious safety training on BP cannon from US Army certified instructors. It was well worth the admission price to the school... those interested might be able to find a school in your area by contacting Rev War or Civil War artillery units, I recommend it to all me hearties...
As fer the rest o' ye, I hae seen a few homemade cannon, most were well researched & built (one was turned on an industrial lathe from a solid 8" cylinder of steel) and all the ones that are in regular use survived a "proofing": Double charge of powder, well rammed, 2 cannonballs (if your gun requires sabots due to the size ball vs size bore, then sabot both) and a long fuse. This is done on acreage, best on hilly acreage aimed into a hill or cliff face. Light the fuse, and run at right angles to the bore to a safe place (behind a stone wall, cliff face, hill, etc.) and wait for the boom. Or do like John and go 3 miles to the nearest burger joint... 5 minutes after the boom (so everything fallng has a chance to) go inspect the damage. Look for swells, cracks, any deformity in the barrel. Any deformity is cause for rejection. (Charlie followed this test with "Fill the bore up to the muzzle with well-rammed powder & light the fuse". His passed both tests.) If the barrel passes, mount it on the carriage.
Then enjoy yer grog in good health, me buckos.
Salamander