So just to be clear, when a box of H&H or other British shells say "6" they mean "7", right?
No when a British box of shells says #6 they mean #6. The British use a different size system than we do. Their #6 just happens to be nearly identical to our #7. There was a time in the US back around the turn of the century last, that in the US in order to get the size desired you had to state not only the size, but also from which Tower. Finally sizes were standardized & sizes of the Tatum Tower of New York became the standard. Under this system an 0 size is .170" diameter & one simply subtracts the size number from this to find the diameter of any given size. Thus a #7 is .170 -.07 or.100". A #7˝ is .170 - .075 or .095"
Can't recall for certain, but that may be Tathum Tower.
