Back in the mid-70's, I bought a between the wars Sauer 16ga as a graduation present to myself when I completed my MA. It had short chambers. I had them lengthened, after which I fired hundreds of high brass pheasant loads through that gun. Back then, a lot of gunsmiths did it regularly. But back then, we didn't have very many gunsmiths--nor gun dealers--who specialized in classic doubles. Thanks to places like this, and to Double Gun Journal, pretty much anyone who has more than a passing interest in a classic sxs knows better now.