That is a good story, if the readers do not read too closely & run the numbers.
The writer of that story was out to lunch, imho. A 4oz ball weighs 1,750gr., if & only if they were actually 1.052" in diameter, which is 4 bore.
16 drams is the normal full load for a 4-bore, whether ctg. or ML, with most chaps not loading over 12 drams - which is 327.6gr. powder. 16 drams is 436.8gr. powder.
4 ounces is 1,750gr. which is 64 drams (27.3gr. is 1 dram), 1 ounce is 437.5gr. Why in the world would anyone shoot 4 ounces of powder out of anything but a 2" or3" cannon on wheels?
With a 4 bore round ball, 12 drams of powder developed enough recoil over 200 pounds to break W.W. Greener's recoil machine, which bottomed at 200 pounds.
This story says they shot 5.3 TIMES more powder than a load that developed well over 200 pounds of recoil?
Sorry - I cannot believe that.
Good story though. F. Selous used a shortened Dutch 4 bore fowler at that time.
Daryl-I will give you the actual weight of a 4 ounce round ball. Frankly we did not weigh the thing as none of us had a scale with 1/10 of a grain divisions that went over 500 grains. And I vaguely remember the bore diameter being 1.005 and 3/10ths taken with an inside micrometer. We took the mould makers word that it was a 4 ounce ball as per the marking on the mould and we did cut off the mounting loop.
As for the powder it was measured by volume in a 100 grain measure of the two piece collapsible type widely available at the time. I am sure you know the one I mean.
As to why we would put that much powder into the bore: We did not know any better at the time. The Internet had not really gotten to this locale yet. Very few places had it, unlike now where a politician can be "fact" checked before they finish their sentence via a smart phone from Kathmandu.
Frankly, many things that some of us have done are undoubted dangerous. I have always liked fast cars, motorcycles, airplanes, .22 caliber rifles, high voltage rf amplifiers and double barreled shotguns. What you call too much gun powder today, in those days, to us, seemed like another day of taking risks. Some people get bored if there is not life or death on the line when they play. Sometimes you play and get acdf surgery and sometimes you don't.
As it is Daryl, we did indeed put a quarter pound of black powder measured by volume in the 1 inch plus bore and what we thought to be a 1/4 pound lead ball, cap the monster and let 'er rip. My buddy was 6'10" and while we never discussed weight he did mention I would need a couple 50 pound bags of dog food strapped around my waist to even be close. So, if you are bored and need something to do over the summer and your health insurance is paid up, you could print the above photo and enlarge it a few times, then get a 1" i.d seamless stainless steel tube, maybe a cheap lock off of ebay (I am pretty sure you won't wear it out although it may break) or maybe you have one in the top drawer that you are not exactly sure what to do with and a chunk of red elm and have one of your own carved out in no time. Then you can give it a go yourself. Heck, start with that 12 drams you mentioned if you like and are unsure.
In the meantime, I will work on getting some photographs of the monster.