Craig, all asked and answered. Not my problem if you don't like the answers....
...you can make shade tree bubba follow the rules the same way we make car dealers follow the rules about not turning back the odometer....
Not a like thing Larry, I'm attempting to show there are problems with the philosophy.
Take for instance my point about your equivocating. As has been umpteenth refried, some folks want 100% registration with annual renewal for all guns just because that's what we do for cars. Thanks for making us all the better. Bubba lengthened a chamber, but said I dunno it was already that way, just like a shoddy brake job doesn't prevent a car from having it's registration renewed.
It would take several hundred years for an American proof house to achieve the romanticism of reading proof marks on a hundred year old British best gun. If saami were down the road from me, I'd still send that special gun off to get the proper marks placed on it, if needed.
