470Rigby

Thanks.

I would agree "that it is a form of Semi-Destructive Testing!" AND
"you have no idea of whether the pressure came withing 1% of failing, or 200%!"

However, I am still glad that the English proof the guns !!!

Re the 30% over the HMSP, I have heard it said that proof now is LESS severe than it was
in the early days.

"Not much of a margin given the vagaries of temperature, bore size and bullet hardness/diameter/bearing surface etc."

That is why I slug all of my bores before firing to make sure. I did a test on about 10 - 12 450/400's and only
found 1 that was a true .408, however in talking to others, .406 - .412 have been found.

Imagine IF someone put a .411 Monolithic in a .406 bore - probably a bit more than a 30% increase.
AT least Woodleigh Steel solids have some "give" in them !!!

Speak soon.

500 Nitro