I short started a ball back in 1972 - in my TC Hawkins. My barrel bulged just like Taylor's did & TC mailed me a new barrel. I've not done it since, but
know of people who have, without any damage to their barrels- just luckier than I was, I suppose- or their barrels had thicker walls - or were made of more stern 'material'.
I have, however double balled a number of times, as well as loading 2 charges each with a ball, then firing it to clear, without damage - slightly more recoil. I figured those were
likely good 'proof' loads. This was in my .69. Good thing my patches seal, isn't it? 85gr. 3F charge + 482gr. ball x 2 + 85gr. = 1049gr. of ejecta. (this was before switching to 85gr.
2F which produces the same velocity)