Many of the 103s that are hitting the market have been imported by Simpson's over the past decade or so. Some of them may have had their chambers lengthened or forcing cones opened up a bit by their original owners in Sweden. I haven't measured the chamber length yet on my 103A but the forcing cone is much more gradual than my 51, which is very abrupt.
The only site that I've found that has any info on the 103s is this one, with very little info and much of it not seeming to be correct:
http://www.shotguns.se/html/hammer_guns_2.htmlThis site -
http://www.skydevaaben.com/allhvamodels/info.xml - used to have a fair number of details of Husqvarna models, but it went down last fall. I managed to save an HTML version of the page as it was cached by Google before it went down. Supposedly it is a verbatim list of all Husqvarna models as published in the Husqvarna museum book. According to it, the 103s were manufactured from 1911-1940 and all but the base 103 model were available with either 65mm or 70mm chambers, I'm assuming the 70mm becoming available after the 165,900 serial number.