My point in asking is that in absence of some rather expensive equipment and expertise that is not readily available outside "the factories" here in the states, any means of "proofing" a home built gun is essentially conjecture. We can add so much powder to the load or a bullet heavier by a certian percentage but without scientific measurement tools we're still only guessing. I'm I wrong?
However if this method, as crude as it seems has been deemed adequate by such a prestigeous establishment... well you get the picture right? It would seem so much simpler than some mystery load who's actual pressure would still be just as much conjecture as the oiled cartridges.

The project I'm working on presently is a .30-30 on a Belgium marked 12 bore hammer gun. I'm at the testing stage and thought I'd give this method a try unless there was any actual negative experience with it by the other members.

4seventy, I respect your opinion and totally agree. However as they've been doing this (proofing) for centuries, most of the time governed by extensive previous experience rather than scientific measurement, I'm inclined to defer to thir methods. After all, many of the prectices in building a double gun or rifle are more "experience" than science. Why should this be any different?

I haven't visited the forum for a while until recently and would love to have Bramble chime in on this. Perhaps a PM is in order...