Well I don't have production numbers on them but would not surprise me in the least to find that Stevens made about a million Double guns, they didn'y bother to SN theirs though until forced to do so by law in 1968. I don't think the numbers built built has much to do with "Best" or even "Strongest" often more to do with "Cheapness". Re T-Model Ford vs Roll's Royce.
Doubt you noticed, but, when you buy a new Purdey O/U, you get a monoblock gun. Regis Darne is laughing out loud, somewhere.
You're Still Ignoring that Regis just "Copied Henri" with that block, he don't have anything to laugh about there. Now "IF" that Purdey is a Sliding Breech then its another matter, but I don't think so.
The mat'l used for the tubes of course has absolutely nothing to do with the principal of joining them. Piepers can be found with Twist, Damascus & Steel tubes all fit to his "One Piece Steel Breech" which was not made of damascus/twist on any of them as you so adamantly implied.
