Lengthened chambers on American guns is a POTENTIAL problem? Wow . . . that's strange. Some guys must not get out a lot. I run into "potential problems" just about every time I visit a gun shop that has very many vintage American doubles on hand. And no need to create an agency. SAAMI already exists.

Here's what it comes down to, for me: I can pick up a Brit or European gun, and just by looking at the proofmarks, I know the original chamber length; I know whether the chambers have been lengthened; I know the original bore diameter (which, when I insert my bore and choke gauge, tells me whether someone's done a significant amount of honing); I may know the load for which the gun was built; and I may be able to tell when the gun was proofed. In contrast, I pick up a vintage American gun, and there's some chance--although less than 50%--that the manufacturer might have marked the original chamber length.

Here's a real world example: Several months back, I bought a Sauer 20ga, imported by Abercrombie and Fitch. My bore and choke gauge tells me that the gun is significantly overbored for a 20, which could mean a lot of honing was done . . . except, right there among the proofmarks, there's this little "19"--which means that the gun left the factory overbored. Eliminates my concern in that area. Same situation on an American double . . . first, I'd have to know what the standard bore diameter was, for that particular manufacturer and for that gauge. That might vary by at least .008 from one maker to another, according to one source I have. Then there's the possibility, somewhat remote but there nevertheless, that someone ordered the gun overbored.

What it comes down to is this: proof and proofmarks, European style, answer a lot of questions relatively quickly and easily that can't really be answered on vintage American guns, without a fair amount of research and some tools. Personally, I prefer having it all spelled out, right there on the barrel flats. But for some, I guess, having more information is a bad thing. Not sure why, but to each his own.