TooTall,
Thanks for the link, very interesting. It goes hand in hand with other info I've been given. Typical first thing to go is the nipple but usually only when subjected to smokeless. I've even been told, by the guy who is reviewing my test plans, that tests have been done where the barrel was filled half way with powder and the other half with PRB's and still did not blow the barrel. I've even heard of guys shooting PRB usingtypical loads of powder out of electrical conduit without rupturing it. Short starting was the most likely way of rupturing a barrel, not overloading. Of course, neither is safe and I wouldn't recommend doing either as a common practice.