Hm.

My understanding of the dynamics of interior ballistics is that interior pressures reach their peak at about one third the way from the breech, or in the neighborhood of seven to nine inches from the breech face, and not in the chamber.

i'll look into my texts and notes and try to figure why I'd been left with that impression but it's one that's been with me for years.

funny too, that's where I've seen most of the deformations in bulged barrels I've seen besides steel shot mishaps in shotguns...

go figure

--Tinker